List of companies of the United Kingdom K–Z

The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK or U.K.) or Britain, is a sovereign country located off the northwestern coast of the European mainland. It includes the island of Great Britain, the northeastern part of the island of Ireland, and many smaller islands. The United Kingdom consists of four constituent countries: England, Scotland, Wales and Northern Ireland.

The United Kingdom is a highly developed country with a market-orientated economy and is a member of the Group of 7 (formerly G8) leading industrialised countries. It is the sixth-largest national economy in the world measured by nominal gross domestic product (GDP), ninth-largest by purchasing power parity (PPP) and twenty first-largest by GDP per capita. In 2017, the UK was the eleventh-largest goods exporter in the world and the eighth-largest goods importer. It also had the second-largest inward foreign direct investment, and the third-largest outward foreign direct investment. The UK left the European Union in 2019, but it remains the UK's largest trading partner. In 2019, the UK had a labour force of 34,280,575 people and, as of 2018, an employment rate of 78.7%.

The service sector contributes around 80% of GDP with the financial services industry being significant, with London as the second-largest financial centre in the world. Britain's aerospace industry is the second-largest national aerospace industry. Its pharmaceutical industry is the tenth-largest in the world. Of the world's 500 largest companies, 26 are headquartered in the UK. The economy is boosted by North Sea oil and gas production; its reserves were estimated at 2.8 billion barrels in 2016, although it has been a net importer of oil since 2005. The size of London's economy makes it the largest city by GDP in Europe.

In the 18th century the UK was the first country to industrialise, and during the 19th century it had a dominant role in the global economy, accounting for 9.1% of the world's GDP in 1870. The Second Industrial Revolution was also taking place rapidly in the United States and the German Empire; this presented an increasing economic challenge for the UK. The costs of fighting World War I and World War II further weakened the UK's relative position. In the 21st century, the UK has faced the challenges of the 2008 banking collapse and the 2020 coronavirus pandemic.

Largest companies
This list shows the UK companies in the Fortune Global 500, which ranks firms by total revenues reported as of September 2019. Only the top five firms are included as a sample.

Notable companies
This is a list of companies of the United Kingdom as well as those first established in the United Kingdom that are no longer British owned, and also including defunct UK companies. Only companies with articles in Wikipedia are included.

K

 * Kaos Films — is a film production company. It formerly held film competitions. It was established in 2001.
 * Kainos Group plc — is a computer software company that provides information technology services and consulting for government departments and agencies, businesses, and organisations. It is headquartered in Belfast, Northern Ireland. It was founded in 1986 as a joint venture between Fujitsu and Queen's University of Belfast. Since then the ownership has changed. In 2022 its revenue was £302 million, with a net income of £35 million.
 * Kays of Scotland — is a manufacturer of curling stones based in Mauchline, Scotland. It was founded in 1851 by William Kay and sons Andrew and Thomas. It is owned by the Wylie family.
 * Keen City — is a film and television production company. Established in 2008, its headquarters is in London.
 * Keepmoat Homes Ltd — is a house building company headquartered in Doncaster, South Yorkshire. It was founded in 1931 by George Bramall and Dick Ogden as Bramall & Ogden. After acquiring Frank Haslam Milan in 1983 it was renamed Keepmoat. In 2012 it was merged with social housing provider Apollo. In 2014 it was acquired by TDR Capital and Sun Capital Partners. In 2021 it was acquired by Aermont Capital. In 2020 its revenue was £406 million, with a net income loss of £14 million.
 * Kelda Group — is a utility company (water and sewage). Established in 1989, its headquarters is in Bradford, Yorkshire. Its subsidiaries are Yorkshire Water and Kelda Water Services.
 * Keller Group plc — is a geotechnical engineering company headquartered in London. It was established in the 1950s as the ground engineering divisin of GKN plc. In 1975 it acquired the German company Johann Keller and was renamed Keller. In 1990 it was the subject of a management buyout from GKN. Its subsidiaries include: Cyntech, GEO-Instruments, Suncoast Post-Tension, Moretrench Industrial, and Phi Group. In 2022 its revenue was £2.9 billion, with a net income of £45 million.
 * Kenley Water Company — was a utility company (water supply) until 1885. In 1885 it merged with Caterham Springwater Company to form the East Surrey Water Company.
 * Kent Reliance — is the trading name of OneSavings Bank plc.
 * Kier Group plc — is a construction, civil engineering, support services, and property management company. It is headquartered in Manchester. It was founded in 1928 by Jorgen Lotz and Olaf Kier as Lotz & Kier, based in Stoke-on-Trent. After Lotz left the company it was renamed J.L. Kier & Co Ltd. It first specialised in concrete engineering before expanding into general contracting and house building. In 1963 it was floated on the London Stock Exchange. In 1973 it was merged with W. & C. French to form French Kier, which was acquired by Beazer in 1986. Hanson bought Beazer in 1991 and then, in 1992, the contracting division known as Kier was the subject of a management buyout. Kier re-entered the housing market with a number of acquisitions and was floated on the London Stock Exchange in 1996. It then expanded its construction, support services, and property management businesses. In 2021 its house building division Kier Living was acquired by Terra Firma Capital Partners and rebranded as Tilia Homes. In 2022 the revenue of Kier Group was £3.2 billion, with a net income of £12 million.
 * Kilchoman distillery — is a producer of Scotch whisky located on Islay, Scotland. It was founded in 2005 by Anthony Wills.
 * Kimbolton Fireworks — was a manufacturer of display fireworks based in Kimbolton, Cambridgeshire. It was founded in 1964 by Ronald Lancaster. It ceased trading in 2019 but the brand name is used by Phoenix Fireworks, and Celtic Fireworks.
 * Kindle Entertainment — is a television production company. Established in 2007, its headquarters is in London.
 * Kingfisher plc – is a multinational retail company with subsidiaries including B&Q, Castorama, Brico Dépôt and Screwfix. It was established in 1982 as Paternoster Stores in order to buyout the British Woolworths chain after which it became Woolworth Holdings. Its acquisition of Woolworths Ltd included B&Q. Further acquisitions included Superdrug and Comet which were sold in the 2000s. In 1989 it was renamed 'Kingfisher plc'. In 1999 it acquired Screwfix, and other acquisitions include Castorama and Brico Dépôt. Woolworths was demerged in 2001. Headquartered in London, its 2022 revenue was £13.1 billion, with a net income of £843 million.
 * Kingdom Bank Ltd — is a Christian bank offering mortgages, savings, loans, and insurance to individuals, churches, charities, and businesses. Headquartered in Beeston, Nottinghamshire; it was founded in 2005 as a subsidiary of the charity Assemblies of God Property Trust. In 2019 it was acquired by a group of christian philanthropists.
 * KP Snacks — is a manufacturer of crisps, nuts, popcorn, and other snacks. It was founded in 1853 in Rotherham, South Yorkshire as Kenyon & Son. Its headquarters is in Slough, Berkshire. Since December 2012 it is owned by Intersnack.

L

 * Ladbrokes Coral — is a gambling company. Established in 1886 in Warwickshire, its headquarters is in London. It was previously known as Ladbrokes, and as Hilton Group plc when it owned Hilton hotels and branding outside of the United States. In 2016 it acquired Gala Coral Group and became Ladbrokes Coral. It is owned by Entain plc.
 * La Fauxmagerie — is a cheesemonger offering vegan cheeses including its own brand, cheese accompaniments, wine, and beer. It operates a retail store, and retail website. It is headquartered in Shoreditch, London. It was founded in 2019 by sisters Rachel and Charlotte Stevens.
 * Lagonda — is a manufacturing company (luxury automobiles). Established in 1906, its headquarters is in Staines-upon-Thames, Middlesex. It also produced shells, guns and other weapons during WWI, and WWII. In 1947 it was bought by Aston Martin.
 * Lakeland Ltd — is a company that operates a retail store chain, catalogue business, and retail website offering kitchenware and other household products. It is headquartered in Windermere, Cumbria. It was founded in 1956 by Alan Rayner as a business supplying farmers with agricultural plastics and home-freezing products, that became Lakeland Plastics. It later specialised in kitchenware and was renamed Lakeland Ltd in 1997.
 * Lambeth Waterworks Company — was a utility company (water) from 1785 to 1903. Headquartered in London, it became part of the Metropolitan Water Board.
 * Lambton Collieries — was a coal mining company from 1896 to 1947. Headquartered in County Durham, it became part of the National Coal Board.
 * Land Securities Group plc (Landsec) — is a commercial property development and investment company. Established in 1944, its headquarters is in London. In 2019 its revenue was £748 million, with net income of £119 million.
 * Laurence Olivier Productions — was a stage and film production company established in the 1950s.
 * Law Debenture Corporation plc — is an investment trust headquartered in London. It also provides fiduciary services for pension funds, trusts, and companies. It was founded in 1899 by Stanley Boulter. In 2022 its revenue was £89 million, with a net income of £43 million.
 * Layton Sports Cars — is a former name of TVR.
 * Leatherhead and District Water — was a utility company (water supply) from 1883 to 1927. It became part of East Surrey Water Company.
 * Leeds Building Society — is a building society offering mortgages, savings, investments, and insurance. It is headquartered in Leeds, West Yorkshire. It originated in 1845 as the Leeds Union Operative Land and Building Society. In 1875 it was registered as the Leeds and Holbeck (Permanent) Building Society. In 2005 it was renamed the Leeds Building Society, and in 2006 was merged with the Mercantile Building Society.
 * Leek United Building Society (trading as Leek Building Society) — is a building society offering mortgages, savings, investments, loans, and insurance. It is headquartered in Leek, Staffordshire. It was founded in 1863 as the Leek United Permanent Benefit Building Society. Its name was changed to Leek United & Midlands Building Society in 1919, and then to Leek United Building Society in 1990.
 * Lees Foods Limited – also known as Lees of Scotland is a manufacturer of confectionery and cakes. It was established in 1931 in Coatbridge, Scotland by John Justice Lees and is still headquartered there. In 1982 Lees established Heather Cameron Foods to produce meringues, later merging it into the Lees brand. In 1987 Lees acquired Gainsborough Chocolates and Fullers of Greenoch. In 1991 Lees was acquired by Northumbrian Fine Foods before returning to independent Scottish ownership in 1993.
 * Left Bank Pictures — is a film and television production company. Established in 2007, its headquarters is in London. Its parent company is Sony Pictures Entertainment.
 * Legal & General Group plc – is a British multinational financial services and asset management company. It offers investment management, mortgages, pensions, annuities, and life assurance. It also offered general insurance before the sale of Legal & General Insurance to Allianz Insurance in 2020. Established in 1836 in London as The New Law Life Assurance Society it was later renamed as Legal & General. Still headquartered in London, it has total assets of £570.5 billion as of 2020. Its revenue in 2020 was £50.2 billion, with a net income of £1.2 billion.
 * Lex Records — is a record label company. Established in 2001, its headquarters is in Camden, London. It was originally an imprint of Warp Records.
 * Lightning Car Company — is a sports car development company. Established in 2007 in Fulham and Peterborough, its headquarters is in Coventry.
 * Limpsfield and Oxted Water Company — was a utility company (water supply) from 1888 to 1930.
 * Linda McCartney Foods — is a producer of vegetarian, and vegan foods such as chilled or frozen meat alternative burgers, sausages, sausage rolls, meatballs, stir fry, pastas, and pies. It was founded in 1991 by Linda McCartney. It was acquired by United Biscuits in 1996; H. J. Heinz in 1999; and the Hain Celestial Group in 2006.
 * Lionsgate UK — is a film production and distribution company. Established in 1997, it was formerly Redbus Film Distribution, and Helkon SK. It is now a subsidiary of Lionsgate.
 * Liontrust Asset Management plc — is an asset management company headquartered in London. It was founded in 1995. In 2016 it acquired Alliance Trust Investment Management, and, in 2019, acquired Neptune Investment Management. In 2022 its revenue was £245 million, with a net income of £59 million.
 * Lister Motor Company — is a manufacturing company (sports cars). Established in 1954 in Cambridge, it was formerly known as George Lister Engineering Limited.
 * Liverpool Hydraulic Power Company — was an energy company (hydraulic power generation and supply) from 1888 to 1971. It was located in Liverpool.
 * LLM Communications — was a political lobbying company. Established in 1997, it is now defunct.
 * Lloyds Banking Group — is a financial services company (banking, life assurance, and pensions). Established in 1995, its headquarters are in Edinburgh, Scotland, and London. It was formed by the merger of Lloyds Bank with TSB. In 2019 its revenue was £42.3 billion, with net income of £2.9 billion.
 * Loch Lomond Distillery Company — is a producer of Scotch whisky that owns the Loch Lomond distillery located in Alexandria, West Dunbartonshire, Scotland. The distillery was founded in 1964.
 * Londis — is a symbol group company with retail units that are mainly convenience stores. 'Londis' is an abbreviation of London District Stores. It was founded in 1959 by Kevin Stanley-Adams. In 2004 it was acquired by Musgrave. In 2015 it was acquired by Booker Group which is now owned by Tesco plc.
 * London Clubs International — is a gaming and hospitality company. Established in 1981, its headquarters is in London. It is owned by Caesars Entertainment.
 * London Electricity Board — was a state owned energy company (electricity supply and distribution, electrical appliances retailer) from 1948 to 1998. Headquartered in London, it was also known as LEB, and London Electricity plc. In 1998 it was acquired by Électricité de France.
 * London Films — is a film and television production company, established in 1932.
 * London Hydraulic Power Company — was an energy company (hydraulic power generation and supply) from 1883 to 1977. It was located in London.
 * London Stock Exchange Group plc — is a stock exchange and financial information company headquartered in the City of London. It owns the London Stock Exchange, Refinitiv, FTSE Russell, and some similar companies. It was founded in 2007. In 2022 its revenue was £7.7 billion, with a net income of -£1.4 billion.
 * Lonmin — is a mining company (platinum group metals). Established in 1909 as the London and Rhodesian Mining and Land Company, it was later known as Lonrho when it briefly owned several UK newspapers. Its headquarters is in London.
 * Lotus Cars — is a manufacturing company (sports and racing cars, and engineering development). Established in 1948 in Hornsey, London, its headquarters is in Hethel, Norfolk. It was formerly known as Lotus Engineering Limited. It has become Group Lotus PLC divided into Lotus Cars and Lotus Engineering.
 * Loughborough Building Society — is a building society offering mortgages, savings, investments, and insurance. It is headquartered in Loughborough, Leicestershire. It was founded in 1867 as the Loughborough Permanent Investment, Land and Building Society.
 * Love Productions — is a television production company. Established in 2004, its headquarters is in London. Its owner is Sky Group.
 * Lowestoft Water Company — was a utility company (water supply, formerly also a gas supplier) from 1853 to 1962. It was formerly known as the Lowestoft Gas, Water and Market Company. In 1962 it merged with the Great Yarmouth Waterworks Company to form the East Anglian Water Company.
 * Lucky Me — is a record label and design studio company. Established in 2007, its headquarters is in Glasgow, Scotland.
 * Ludger Limited — is a biotechnology company (glycoprofiling technology). Established in 1999, its headquarters is in Oxford.
 * Lush – is a company that produces and sells vegan or vegetarian cosmetic products such as creams, soaps, shampoo, bath bombs, moisturisers, showergels, lotions, scrubs, and masks. It operates a multinational retail store chain, and a retail website. Some of its stores also have spa facilities such as massage and facials. It is headquartered in Poole, Dorset. It was founded in 1995 by Mark Constantine, his wife Mo Constantine, and five other founders. Between 2003 and 2009 it also operated the brand and branded stores named 'B Never' (B Never Too Busy To Be Beautiful).
 * Luther Pendragon — is a public relations company. Established in 1992, its headquarters is in London.

M

 * M&Co. (company name is Mackay's Stores) – is a clothing and homeware retail company. Established in 1834 by Len McGeoch as a pawnbrokers in Paisley, Renfrewshire Scotland, it converted to a clothing retailer from 1953. Now headquartered in Inchinnan, Scotland, it has over 300 stores including overseas. In 2019 its revenue was £193 million, with a net income of £0.88 million.
 * M&G plc — is a financial services investment company headquartered in London. It was founded in 1931 as the Municipal & General Securities Company. In 1999 M&G Investments was acquired by Prudential plc. It was demerged in 2019. It has 2 subsidiaries: M&G Real Estate, and Infracapital. In 2022 its revenue was £6.5 billion, with a net income loss of £1.6 billion.
 * Mace Group Ltd — is a construction and business services company. It is headquartered in London. It was founded in 1990 by a group of construction professionals led by Ian Macpherson. In 2022 its revenue was £1.9 billion, with a net income of £22 million.
 * Mackies of Scotland – is a private food manufacturing company specialising in ice cream, potato crisps, and chocolate confectionery. Founded in 1912 as a dairy farm, the milk retail business was divested in 1997. Ice cream production began in 1986, crisps from 2009 to 2022, and chocolate in 2014. It is headquartered in Rothienorman, Scotland. In 2018 its revenue was £13.9 million, with an operating income of £1.3 million.
 * Magic Light Pictures — is a film and television production company that also manages the children's brand 'The Gruffalo'. Headquartered in London, it was founded in 2003 by film producers Martin Pope and Michael Rose.
 * Magma Pictures — is a film production company headquartered in London. It was founded in 2004 by film directors James Walker and Ed Boase. Its sister company is Young Film Academy which provides film education.
 * Magnet Kitchens — is a designer, manufacturer, and retailer of fitted kitchens, kitchen units, and joinery. It also sells kitchen appliances. It operates a retail store chain and retail website using the brands 'Magnet' for retail customers, and 'Magnet Trade' for registered trade customers. It is headquartered in Darlington, County Durham. It was founded in 1918 by Tom Duxbury. In the 1920s Magnet began the first mass-production of joinery, and door and window products, with kitchen products added in 1970. By the 1970s it had a joinery store chain. In 1975 it was merged with timber company Southern-Evans to form Magnet & Southerns. In 1984 it was floated on the London Stock Exchange. In 1985 it began opening kitchen retail showrooms. In 1989 the Southern-Evans business was sold, and then there was a management buyout which failed and left the lenders in control. In 1990 separate retail and trade divisions were introduced. In 1994 it was acquired by Berisford who sold it to Nobia in 2001.
 * Maldon Sea Salt — is a salt producing company based in Maldon, Essex. It was founded in 1882 after being part of a nearby coal firm.
 * Manchester Collieries — was a coal mining company that operated from 1929 to 1947. Headquartered in Walkden, it was formed by the merger of a number of independent mining companies. It was nationalised in 1947.
 * Manchester Hydraulic Power — was a hydraulic power generation and supply company ran by Manchester Corporation from 1894 to 1972. It was headquartered in Manchester.
 * Mancunian Films — was a film production company that operated from 1934 to 1954. It was founded by film producer, director and screenwriter John E. Blakeley in London as Blakeley's Productions until it was renamed The Mancunian Film Distributors, Ltd. In 1947 it relocated to Dickenson Road Studios, Rusholme, Manchester.
 * Man Group plc — is a multinational financial services company providing investment funds for institutional and private investors. It is headquartered in London. It was founded in 1783 by James Man as a sugar broker. It continued to trade in commodities through the 19th and 20th centuries before diversifying into financial services. It was renamed ED&F Man in 1869. In 2000 it was split into Man Group for financial services, and ED&F Man for commodities trading. In 2022 its revenue was $1.7 billion, with a net income of $608 million.
 * Mansfield Building Society — is a building society offering mortgages, savings, and insurance. Headquartered in Mansfield, Nottinghamshire; it was founded in 1869.
 * MANWEB (Merseyside and North Wales Electricity Board) — was a nationalised energy company supplying and distributing electricity. Established in 1947, it was privatised in 1990, when it became MANWEB plc. In 1996 it was purchased by Scottish Power and is now part of SP Energy Networks.
 * Marconi Electronic Systems — was a defence systems company (naval vessels, radio, radar, munitions, spacecraft, avionics) from 1897 to 1999. Headquartered in Chelmsford, Essex, it was formerly known as Marconi Company, and GEC-Marconi when the General Electric Company became its parent company in 1968. In 1999 it was merged with British Aerospace to form BAE Systems.
 * Marella Cruises — is a transport company (cruise line). Established in 1973, it was formerly known as Thomson Cruises. Its parent company is TUI AG.
 * Market Harborough Building Society — is a building society offering mortgages, and savings. Headquartered in Market Harborough, Leicestershire; it was founded in 1870.
 * Marks & Spencer Group plc – is a British multinational retail company offering clothing, home products, food, and energy. It was established in 1884 in Leeds by Michael Marks and Thomas Spencer. Now headquartered in London, its total revenue for 2020 was £10.1 billion with a net income of £27.4 million.
 * Marlin Sportscars — is a manufacturer of sports cars. Established in 1979 in Plymouth, Devon, its headquarters is in Crediton, Devon.
 * Marsden Building Society (trading as the Marsden) — is a building society offering mortgages, savings, investments, loans, and insurance. Headquartered in Nelson, Lancashire; it was founded in 1860.
 * Marshalls plc — is a manufacturer of natural stone and concrete hard landscaping products, water management systems, street furniture, and landscape protection products. It also operates its own quarries. It is headquartered in Elland, West Yorkshire. It was founded in 1890 by Solomon Marshall. In 2022 it acquired roof manufacturer Marley. Its revenue in 2022 was £719 million, with a net income of £26 million.
 * Marylebone Studios — was a film production company. Established in the late 1930s, its headquarters was in London.
 * Marv Films — is a film production company. Established in 2004, its headquarters is in London.
 * Matalan Retail Ltd — is a company that operates a fashion and homeware retail store chain and retail website. It also produces clothing and other items. It is headquartered in Knowsley, Merseyside. It was founded in 1985 by John Hargreaves. In 1998 it was floated on the London Stock Exchange and then taken private again in 2006 by the Hargreaves family who remain the owners.
 * Mathmos — is a manufacturer of lighting products headquartered in Poole, Dorset. It is best known for the lava lamp which was invented by Edward Craven Walker who founded the company in 1963 as Crestworth. Production for the European market took place at Crestworth while the product was licensed for other markets. The company was renamed Mathmos in 1992.
 * Mayflower Productions — is a film production company, 1937–1954. It was formerly known as Mayflower Pictures.
 * McCallum Ltd — is a manufacturer of great highland bagpipes based in Kilmarnock, Scotland. It was founded in 1998 by Stuart McCallum and Kenny Macleod.
 * McCarthy Stone — is a developer and manager of retirement communities. It is headquartered in Bournemouth, Dorset. It was founded in 1977 by John McCarthy and Bill Stone. After several changes of ownership, it was acquired by Lone Star Funds in 2020. Its total revenue in 2019 was £725 million, with a net income of £34 million.
 * McColl's — is a company that operates a retail chain of convenience stores and newsagents. It trades under the names 'Morrisons Daily' and 'McColl's' for convenience stores, 'Martin's' for newsagents and pound shops, and 'RS McColl' for some of its Scottish stores. Some stores include in-store post offices. It is headquartered in Brentwood, Essex. It was founded in 1973. In 1998 the Martin's and RS M'Coll's newsagent chain was acquired by TM Retail. In 2006 there was a management buyout followed by TM Retail being renamed 'Martin McColl Ltd'. In 2014 it was floated on the London Stock Exchange as McColl's Retail Group. In 2016 it acquired 298 stores from The Co-operative Group. In 2022 it was put into administration and then acquired by Morrisons.
 * McLaren Group — is an automotive manufacturer based at the McLaren Technology Centre in Woking, England. It was founded in 1985 by Ron Dennis.
 * McLaughlin & Harvey Holdings — is a construction and civil engineering company. It is headquartered in Mallusk, County Antrim, Northern Ireland. It was founded in 1853 by Henry McLaughlin and William Harvey. Its main subsidiaries are Laughlin & Harvey Ltd in Northern Ireland, and Trench Holdings Ltd in Scotland. In 2007 it acquired Barr Construction.
 * McLean Homes — was a house building company headquartered in Wolverhampton, West Midlands. It was founded in 1920 by John McLean. In 1969 it acquired Midland & General Developments. In 1972 it was acquired by Tarmac Group. In 1995 it was acquired by George Wimpey in an asset swap. The use of the brand ended in 1996.
 * Mecca Bingo — is a gambling company (bingo clubs, and online gambling). Established in 1961, its headquarters is in Maidenhead. Formerly known as Top Rank, its parent company is The Rank Group.
 * Mecca Leisure Group — is a leisure and hospitality company (nightclubs, cafes, casinos, hotels, theme parks). Established in 1933 as Mecca Agency Ltd, its headquarters is in London. In 1990 it became part of The Rank Group.
 * Medherant — is a pharmaceuticals company that manufactures transdermal patches. Established in 2015, its headquarters is in Coventry.
 * Melrose Industries – is a manufacturing company that invests in and divests engineering companies. Established in 2003, its headquarters is in London. Its main subsidiaries are Brush Turbogenerators, GKN, and Nortek. In 2020 its revenue was £8.7 billion, with a net income of £533million.
 * Melton Building Society is the trading name of The Melton Building Society.
 * Mercantile Investment Trust plc — is an investment trust focused on UK medium and smaller companies. Headquartered in London; it was founded in 1884. It is managed by JPMorgan Chase.
 * Merchant Ivory Productions — is a film production company, established in 1961.
 * Merchants Trust plc — is an investment trust focused on Footsie 100 companies. It is headquartered in London. It was founded in 1889 by Robin Benson.
 * Merton Park Studios – was a film production and studio company that operated from 1930 to 1967.
 * Merlin Cinemas — is a cinema chain company. Established in 1990, its headquarters is in England.
 * Metcalfe's Food Company — was a private food company founded in 2010 by Julian Metcalfe. Headquartered in London, it manufactured snack food under the Metcalfes Skinny brand and retailed grocery under the Itsu brand. In 2015 the company was split into Metcalfes Skinny, and Itsu.
 * Metcalfes Skinny — is a snack food company that originated in 2009 as part of Metcalfe's Food Company. In 2015 it was split out as a separate company, and in 2016 it was purchased by Snyder's-Lance.
 * Metro Bank plc — is a retail and commercial bank headquartered in London. It was founded in 2010 by Anthony Thomson and Vernon Hill. Its acquisitions include SME Finance, and Retail Money Market Ltd.
 * Metropolitan Water Board — was a state owned utility company supplying water and dealing with sewage. It operated from 1903 to 1974. Formed from the amalgamation of eight private water companies, it became part of Thames Water.
 * MG Car Company — was a manufacturing company (sports and racing cars) from 1930 to 1972. MG Cars were first produced in 1924, at Oxford.
 * MG Motor — is a manufacturing company (sports and racing cars). Established in 2006, its headquarters is in Longbridge, Birmingham. Its parent company is SAIC Motor.
 * MGM British Studios — is a film production company, 1936–1970. It was a subsidiary of MGM.
 * MGM-EMI — is a film production and distribution company. See EMI Films.
 * MHP Communications — is a public relations company. Established in 2010, its headquarters is in London.
 * Miller Homes Ltd — is a house building company headquartered in Edinburgh, Scotland. It was founded in 1934 by Sir James Miller. It also became a construction company during WWII and thereafter. In 2005 it acquired Fairclough Homes. In 2014 it sold its construction division to Galliford Try. In 2022 it was acquired by Apollo Global Management.
 * Minera Mining Company — was a lead mining company from 1845 to 1914. It was located in Minera, Wales.
 * Minera Lime Company — was a mining company (lime quarries and kilns) from 1852 to 1972. It was located in Minera, Wales.
 * Minerals Separation, Limited — is a mining company (ore extraction processes), c1903-c1950s. It was headquartered in London.
 * Mirisch Films — was a film and television production company from 1962 to 1982. It was a subsidiary of The Mirisch Company.
 * Mitchells & Butlers plc (M&B) — is a hospitality company that runs over 1700 managed pubs, bars, and restaurants in the UK and Germany. Its brands include: All Bar One, Miller & Carter, Nicholson's, Toby Carvery, Harvester, Browns Restaurants, O'Neills, and the Alex brand in Germany. It is headquartered in Birmingham. It has its roots in the Mitchells & Butlers Brewery which was founded in 1898, and merged into Bass Brewery in 1961. In 2000 Bass rebranded as Six Continents and in 2003 was split into InterContinental Hotels Group for the hotel's business, and Mitchells & Butlers for the pubs, bars, and restaurants business. In 2022 its revenue was £2.2 billion, with a net income of £13 million.
 * M J Gleeson Group plc — is a housing company focused on house building in urban regeneration, residential property management, and land trading. Headquartered in Sheffield, South Yorkshire, it was founded in 1903.
 * Mo-Car Syndicate — was an automobile manufacturing company that operated from 1895 to 1905. Headquartered in Glasgow, Scotland, it later became Arrol-Johnston.
 * Mofilm — is an advertising company. Established in 2007, its headquarters is in London.
 * Molten Ventures plc — is a venture capital company investing in technology companies. It is headquartered in London. It was founded in 2006 by Stuart Chapman as Esprit Capital. It was renamed Draper Espirit in 2015 and then Molten Ventures in 2021. In 2022 its revenue was £351 million, with a net income of £300 million.
 * Mond Nickel Company — was a mining company that operated from 1900 to 1929. It was merged with the International Nickel Company.
 * Mondi plc — is a multinational packaging and paper manufacturer. Founded in 1967 in South Africa, it is now headquartered in Weybridge U.K. and Vienna, Austria. In 2022 its total revenue was €8.9 billion, with a net income of €1.5 billion.
 * Moneysupermarket.com Group plc — is a price comparison company headquartered in Ewloe, Wales. It operates the price comparison websites moneysupermarket.com, and travelsupermarket.com, and the financial information website moneysavingexpert.com. It was founded in 1987 by Simon Nixon and Duncan Cameron as a mortgage subscription business before switching to a price comparison business in 1993. In 2019 it acquired Maple Syrup Media which is the owner of cash-back website Quidco. In 2022 its revenue was £387 million, with a net income of £69 million.
 * Monks Investment Trust plc — is an investment trust headquartered in Edinburgh, Scotland. In 1929 it was founded with 2 other trusts by a group of investors headed by Lord Geddes. The other trusts were The Friars Investment Trust, and The Abbots Investment Trust. In 1931 Baillie Gifford took over the management of the 3 trusts. In 1968 the 3 trusts were merged into Monks Investment Trust which acquired the total share capital.
 * Monmouthshire Building Society — (Cymdeithas Adeiladu'r Sir Fynwy) — is a building society offering mortgages, savings, and insurance. It is headquartered in Newport, Wales. It was founded in 1869 as the Monmouthshire and South Wales Permanent Investment Benefit Building Society. After several preceding name changes, it was renamed the Monmouthshire Building Society in 1969.
 * Monzo Bank Ltd (trading as Monzo) — is an online bank offering current accounts, savings accounts, lending products, and virtual credit cards, for personal and commercial customers. Headquartered in London; it was founded in 2015 by Tom Blomfield, Jonas Huckestein, Jason Bates, Paul Rippon and Gary Dolman. In 2023 its revenue was £355 million, with a net income loss of £116 million.
 * Moonpig plc — is an internet-based company offering personalised greetings cards, flowers, and small gifts. It is headquartered in London and Guernsey. It was founded in 2000 by Nick Jenkins. In 2011 it was acquired by Photobox Group. In 2019 Moonpig was moved from Photobox Group to form Moonpig Group which also included Dutch card company Greetz. In 2021 it was floated on the London Stock Exchange. In 2022 its revenue was £304 million, with a net income of £31.4 million.
 * Morgan Advanced Materials — is a manufacturer of specialist industrial products using carbon, advanced ceramics, and composites. It is headquartered in Windsor, Berkshire. It was founded in 1856 by the six Morgan brothers (William, Thomas, Walter, Edward, Octavius and Septimus) as the Patent Plumbago Crucible Company that manufactured crucibles. In the 1870s it was renamed Morgan Crucible until 2013 when it became Morgan Advanced Materials. Its subsidiaries are Morgan Technical Ceramics Ltd and Thermal Ceramics UK Ltd. In 2022 its revenue was £1.1 billion, with a net income of £96 million.
 * Morgan Motor Company —is a manufacturer of luxury cars. Established in 1910, its headquarters is in Malvern, Worcestershire.
 * Morgan Sindall plc — is a construction, civil engineering, and regeneration company that operates in the public, regulated, and private sectors. Headquartered in London, it was founded in 1977. In 2022 its revenue was £3.6 billion, with a net income of £60 million.
 * Morrisons – Wm Morrison Supermarkets plc, trading as Morrisons, is a supermarket chain. Founded in 1899 by William Morrison, its headquarters is in Bradford. Its 2020 revenue was £17.5 billion, with a net income of £348 million. In October 2021 it was confirmed that the company had been acquired by US private equity company Clayton, Dubilier & Rice.
 * Moss Bay Hematite Iron and Steel Company — was a metals and mining company from 1876 to 1909. Headquartered in Workington, Cumberland, in 1909 it was amalgamated into Workington Iron and Steel Company.
 * Motorway Ltd — operates a used car marketplace. Established in 2017, it uses an online selling platform to allow users to sell their car to dealers. It is based in London and Brighton, East Sussex.
 * Mountain Warehouse Ltd — is a company that operates a multinational retail store chain and retail website offering outdoor clothing, sportswear, footwear, camping equipment, and accessories. It also produces these categories of products for its own brand. It is headquartered in Victoria, London. It was founded in 1997 by Mark Neale as the retail division of Karrimor International. In 1999 it was acquired by Cullinan Holdings who rebranded the Karrimor stores as 'Mountain Warehouse'. In 2002 it was acquired by NBGI Private Equity. In 2007 it was the subject of a management buyout. Its subsidiaries include Zakti, and Neon Sheep.
 * Movie House Cinemas — is a cinema chain company, headquartered in Belfast, Northern Ireland.
 * Moving Picture Company — is a film company (visual effects). Established in 1970, its headquarters in London. Its parent company is Technicolor SA.
 * Mr Q Media — was the former name of film company Suited Caribou Media.
 * Mr Films — was a film company (studios and film production) that operated from 1973 to 1991. It was headquartered in London.
 * MUBI — is a company that operates a global film streaming platform that also includes a film news and criticism webzine called Notebook, and a social networking section. It is also a film producer and distributor. It is headquartered in London. It was founded in 2007 by Efe Cakarel as 'The Auteurs'. In 2010 it was renamed MUBI. In 2022 it acquired the film production company The Match Factory.
 * Multitude Media — is a public relations company. Established in 2009, its headquarters is in London.
 * Muir Group plc — is a house building and timber processing company. It is headquartered in Inverkeithing, Fife, Scotland. It was founded in 1973 by John Muir.
 * Murray Income Trust plc — is an investment trust focused on UK equities. It was established in 1923 as the Caledonian Trust Company, and in 1979 became the Murray Caledonian Investment Trust, before becoming the Murray Investment Trust in 1984. First managed by Murray Johnstone, it is now managed by Abrdn plc.
 * Murray International Trust plc — is an investment trust focused on worldwide equities. Headquartered in Edinburgh; it is managed by Abrdn plc.
 * musicMagpie — is an online retail company buying and selling secondhand electronics, computer games, games consoles, books, cds, and dvds. It is headquartered in Stockport and Macclesfield. It was founded in 2007 by Steve Oliver and Walter Gleeson.
 * My Local Bobby — is a security company based in London. It was founded in 2016 by former police officers David McKelvey and Tony Nash. It is owned by TM Eye Ltd.

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 * Napoleon Films – was a film production company. See G.B. Samuelson Productions.
 * National Commercial Bank of Scotland — was a financial services company offering banking that operated from 1959 to 1969. It was formed by a merger of the National Bank of Scotland with the Commercial Bank of Scotland. In 1969 it was merged with the Royal Bank of Scotland to form the National and Commercial Banking Group, which was later renamed the Royal Bank of Scotland Group and then NatWest Group.
 * National Counties Building Society — is a building society offering mortgages, savings, investments, loans, and insurance. It is headquartered in Epsom, Surrey. It was founded in 1896 as the Fourth Post Office Mutual Society. In 1972 it was renamed the National Counties Building Society. In 2014 it founded the Family Building Society.
 * National Grid plc — is a multinational electricity and gas transmission company. It also produces electricity and gas in the Northeastern United States. Established in 1990, its headquarters is in London. Formerly known as National Grid Transco, its predecessor was the Central Electricity Generating Board. In 2022 its revenue was £18.2 billion, with a net income of £2.3 billion.
 * National Interest Picture Productions — was a film production company that operated from 1925 to 1978. It was founded by film director Albert E. Hopkins and cinematographer Reginald Wyer. Headquartered in London; it was formerly known as Publicity Pictures.
 * National Power — was an energy company producing gas and electricity that operated from 1990 to 2001. Headquartered in London, it was formerly part of the Central Electricity Generating Board. In 2000, it was demerged into Innogy plc and International Power.
 * Nationwide Building Society — is the world's largest building society by membership. It operates a branch network and online services offering mortgages, savings, loans, bank accounts, credit cards, and insurance. Headquartered in Swindon, Wiltshire; it derives from the mergers of 250 building societies. It was founded in 1884 as the Co-operative Permanent Building Society. After leaving the British Co-operative Union in 1970 it was renamed the Nationwide Building Society. In 1987 it merged with the Anglia Building Society to become the Nationwide Anglia Building Society until 1991 when it reverted to Nationwide. In 2007 it merged with the Portman Building Society before acquiring the Cheshire Building Society and Derbyshire Building Society in 2008 and the Dunfermline Building Society in 2009. Its subsidiaries include: Nationwide International, Nationwide Syndications, The Mortgage Works, UCB Home Loans, Derbyshire Home Loans, and E-Mex Home Funding. In 2022 its revenue was £3.86 billion, with a net income of £1.25 billion.
 * Natural Nylon — was a film and theatre production company that operated from 1997 to 2003.
 * National Westminster Bank plc (trading as NatWest) — is a bank providing financial services such as mortgages, savings, loans, investments, and insurance. Established in 1968, its headquarters is in Bishopsgate, London. It was formed from the merger of National Provincial Bank with Westminster Bank. Its parent company is NatWest Holdings, the "ring-fenced" business of NatWest Group.
 * NatWest Holdings Limited — is a retail banking holding company which includes NatWest, Royal Bank of Scotland, Coutts, and Lombard North Central. Established in 2016, its headquarters is in London. Its parent company is the NatWest Group.
 * NatWest Group — is a holding company containing NatWest Holdings Limited (NatWest, Royal Bank of Scotland, Ulster Bank, NatWest Markets, Coutts, and Lombard North Central), RBS International, Drummonds Bank, and Isle of Man Bank. Established in 1969, its headquarters is in Edinburgh, Scotland. It was formed from the merger of the National Commercial Bank of Scotland with the Royal Bank of Scotland. It was formerly known as National and Commercial Banking Group and later as the Royal Bank of Scotland Group. In 2022, its revenue was £13.1 billion, with a net income of £3.5 billion.
 * NatWest Markets plc — is the investment banking component of the NatWest Group. Established in 2016, its headquarters is in Bishopsgate, London.
 * NB Private Equity Partners — is an investment company established in 2009. It is managed by Neuberger Berman.
 * Neal Street Productions — is a film, television and theatre production company. Headquartered in Covent Garden, London; it was founded in 2003 by Sam Mendes, Pippa Harris, and Caro Newling. In 2015 it was acquired by All3Media.
 * Nelsons — is an alternative medicines company producing homeopathic medicines, complementary medicines, and  natural medicines. Headquartered in Wimbledon, London; it was founded in 1866 by Ernst Louis Armbrecht and Charlotte Nelson. It was formerly known as Ambrecht, Nelson & Co, and as A. Nelson & Co.
 * NetResult.uk.com Ltd (trading as NetResult) — is an IT company offering IT support for businesses, consultancy, cybersecurity and other IT services. Headquartered in Mold, Flintshire; it was founded in 1996 by Nick Bell.
 * NetResult Ltd — was a creator of websites and related digital marketing. Headquartered in Brighton, East Sussex; it operated from 1995 to 1997.
 * Newbury Building Society — is a building society offering mortgages, and savings. Headquartered in Newbury, Berkshire; it was founded in 1856.
 * Newcastle Building Society — is a building society offering mortgages, savings, investments, and insurance. It is headquartered in Newcastle upon Tyne, Tyne and Wear. It was formed in 1980 by the merger of the Grainger Permanent Building Society (founded 1861) with the Newcastle Permanent Building Society (founded 1863). It merged with the Universal Building Society in 2006; and with the Manchester Building Society in 2023.
 * NewDay Limited — is a financial services company offering credit products such as store cards. Established in 2000, its headquarters is in Kings Cross, London. It was formerly known as SAV Credit.
 * New Look Retailers Ltd (trading as New Look) — is a company that operates a clothing retail store chain, and a retail website. It is headquartered in Weymouth, Dorset and London. It was founded in 1969 by Tom Singh. In 2015 it was acquired by Brait SE (SA).
 * New Moon — is a film production company. Headquartered in Soho, London; it was founded in 1996 by Caroline Rowland.
 * New River Company — utility company (water supply), landowner and residential development, 1619–1904. It became part of the Metropolitan Water Board in 1904.
 * Newton, Chambers & Co. — mining and manufacturing company (coal and ironstone mining, iron production, industrial construction, disinfectant, production of army vehicles such as the Churchill tank during WWII, construction equipment, wax polishes and wood stains, oil central heating) 1789–2001.
 * Next plc — is a British multinational clothing, footwear, and home products retailer. Founded in Leeds in 1864 by Joseph Hepworth as Joseph Hepworth & Sons, it is now headquartered in Enderby, Leicestershire. in 2022 its total revenue was £4.3 billion, with a net income of £677 million.
 * N. Hingley & Sons — mining and manufacturing company (cable chains, anchors, coal mining, iron works), 1838–1986. It was established in Cradley, West Midlands.
 * Night Slugs — record label company. Established in 2010, its headquarters is in London.
 * Nisa Retail Limited — retail and wholesale co-operative company (groceries). Established in 1977, its headquarters is in Scunthorpe, North Lincolnshire. Its parent company is The Co-operative Group.
 * Nexus Studios — is a film production company. Established in 2000, its headquarters is in London.
 * Noble Foods – is a limited company producing poultry products and desserts. It is the United Kingdom's largest egg producer. It was founded in 2006 by the merger of Deans Foods with Stonegate which was later divested. Headquartered in Standlake, Oxfordshire, it owns the dessert manufacturer Gü as a subsidiary.
 * Norbrook Group — is a pharmaceuticals company (veterinary medicines). Established in 1969, its headquarters is in Newry, Northern Ireland.
 * North Atlantic Smaller Companies Investment Trust — is an investment trust targeting smaller companies in North America. Established in 1973 as the Montagu Boston Investment Trust, it became the Consolidated Venture Trust in 1984, and the North Atlantic Smaller Companies Investment Trust in 1993.
 * North British Railway (NBR) — was a Scottish railway company with routes from north England through the Scottish Borders and southern Scotland to Edinburgh and Glasgow and north to Mallaig and Aberdeen. It was headquartered in Edinburgh. Founded in 1844, throughout its history it was expanded and acquired many other rail companies. It manufactured locomotives, coaches, and wagons at Cowlairs railway works, Glasgow. It also owned docks, Clyde steamers, hotels, road haulage, and part-owned the Forth Railway Bridge. In 1923 it was amalgamated with a number of other railway companies to form the London and North Eastern Railway (LNER).
 * North Eastern Gas Board — was a state owned gas supplier that operated from 1949 to 1973. It became part of British Gas.
 * North Eastern Railway (NER) — was a railway company that had routes through Yorkshire, County Durham, Northumberland, Westmorland, and Cumberland in England as well as Roxburghshire in Scotland. It was headquartered in York, North Yorkshire. It was founded in 1854 by the amalgamation of a number of existing railway companies. It continued its acquisitions throughout its history, including the Stockton and Darlington Railway in 1863. Its largest stations included York, Newcastle, and Leeds. Railway coaches were built at its Holgate Road carriage works, York. It also owned docks and ships, and part-owned the Forth Railway Bridge. In 1923 it was amalgamated with a number of other railway companies to form the London and North Eastern Railway (LNER).
 * North of Scotland Hydro-Electric Board — was an electricity generator and supplier that operated from 1943 to 1990. Headquartered in Edinburgh, Scotland, it was succeeded by Scottish Hydro Electric.
 * North Thames Gas Board — was a state owned gas supplier that operated from 1949 to 1972. It became part of the British Gas Corporation.
 * North Western Gas Board — was a state owned gas supplier that operated from 1949 to 1973. In 1973 it became part of British Gas.
 * Northern Coachbuilders (NCB) — manufacturing company (automobiles). See Smith Electric Vehicles.
 * Northern Electric — energy company (electricity supply and distribution), 1947–1996. Headquartered in Newcastle upon Tyne, it was formerly the North Eastern Electricity Board. In 1996 it was acquired by CalEnergy.
 * Northern Gas Networks — energy company (gas supply and distribution). Established in 2005, its headquarters is in Leeds, Yorkshire.
 * Northern Ireland Electricity Networks — energy company (electricity transmission and distribution). Established in 1973, it was formerly the Northern Ireland Electricity Service. Its parent company is ESB Group.
 * Northern Ireland Water — state owned utility company (water supply and sewage). Established in 2007, it was formerly the Northern Ireland Water Service.
 * Northern Powergrid — energy company (electricity distribution). Established in 1996, its headquarters is in Newcastle upon Tyne. It was formerly CE Electric UK Funding Company. Its parent company is Berkshire Hathaway Energy.
 * Northern Rock — financial services company (banking; formerly it was a building society), 1965–2012. Headquartered in Gosforth, Newcastle upon Tyne, it was formed by the merger of the Northern Counties Permanent Building Society with the Rock Building Society. It was nationalised in 2008, and in 2010 it was mainly subsumed by Virgin Money UK plc with the exception of the high risk mortgage book which was renamed Northern Rock (Asset Management) and remained nationalised until 2016 when it was sold to Cerberus Capital Management.
 * Northumbrian Water — utility company (water supply and sewage). Established in 1989, its headquarters is in Durham. It was preceded by the Northumbrian Water Authority. Its parent company is Northumbrian Water Group.
 * Northumbrian Water Group — holding company for several water utility companies including Northumbrian Water and Essex and Suffolk Water. Established in 1989, its headquarters is in Durham. In 2011 it was acquired by CK Infrastructure Holdings.
 * NORWEB — energy company (electricity supply and distribution), 1948–1995. It was formerly the North Western Electricity Board. In 1995 it was acquired by North West Water and became part of North West Electricity Networks.
 * Nottingham Building Society (trading as The Nottingham) — is a building society offering mortgages, savings, bankings, investments, and insurance. Headquartered in Nottingham, Nottinghamshire; it was founded in 1849 as the Nottingham Permanent Benefit Building Society. In 1970 it acquired the Grantham Building Society.
 * Nottingham Corporation Gas Department — state owned power company (production and supply of coal gas), 1874–1947. Headquartered in Nottingham, it was preceded by Nottingham Gas Light and Coke Company. In 1947 it became part of the East Midlands Gas Board.
 * Npower — energy company (electricity generator and supplier). Established in 2000, its headquarters is in Swindon, Wiltshire. It was formerly known as Innogy plc, and RWE npower. Its parent company is Innogy.
 * Nuclear Electric — energy company (nuclear power generation), 1990–1995. Headquartered in London, it was formerly part of the Central Electricity Generating Board. In 1995 it became part of British Energy.
 * Numatic International Ltd — is a manufacturer of domestic, commercial, and industrial cleaning and maintenance equipment. Its main product is the Henry vacuum cleaner. It is headquartered in Chard, Somerset. It was founded in 1969 by Chris Duncan. It has 8 subsidiary companies located in France, South Africa, Germany, The Netherlands, Switzerland, Portugal, Spain, and Italy.
 * Number 9 Films — is a film production company. Established in 2002, its headquarters is in London.

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 * Oakhurst Productions — was a film production company, that operated from the late 1960s to 1970.
 * Ocado plc — is an internet grocery retail company that also licenses grocery technology. It is headquartered in Hatfield, Hertfordshire. It was founded in 2000 by Jonathan Faiman, Jason Gissing, and Tim Steiner. In 2022 its revenue was £2.5 billion, with a net income loss of £481 million.
 * Octopus Capital Ltd — trading as Octopus Group is a holding company that includes energy company Octopus Energy, financial advice company Octopus Money, investment company Octopus Investments, venture capital fund Octopus Ventures, and property company Octopus Real Estate. Founded in 2000; it is headquartered in London.
 * Octopus Energy Group — is an international energy company generating and supplying electricity, including sustainable energy. It is headquartered in London. It was founded in 2015 as a subsidiary of Octopus Capital Ltd. In 2021 it acquired sister company Octopus Renewables that invests in sustainable energy generation. It also supplies software to other energy companies.
 * Odeon Cinemas — is a cinema chain company. Established in 1928, its headquarters is in Brierley Hill, Staffordshire.
 * Ogle Design — design consultancy company (former automobile manufacturer). Established in 1954, its headquarters is in Letchworth, Hertfordshire.
 * One Horizon Group, Plc.— is a technology and media acquisition company, headquartered in London.
 * OnePoll — market research company. Established in 2002, its headquarters is in London.
 * OneSavings Bank plc (trading as Kent Reliance) — is a bank offering mortgages, loans, and savings. Headquartered in Chatham, Kent; it was founded in 1898 as the Chatham & District Reliance Building Society. In 1986 it was merged with the Herne Bay Building Society and renamed as 'Kent Reliant Building Society'. In 2010 J.C. Flowers & Co. acquired a stake in the company to form OneSavings plc which was renamed 'OneSavings Bank plc' in 2011. In 2014 it was floated on the London Stock Exchange. In 2019 it was merged with Charter Court Financial Services. In 2022 its revenue was £775 million, with a net income of £410 million. It is owned by OSB Group plc.
 * OpenBet — gambling company (software). Established in 1996, its headquarters is in Chiswick, London. It is owned by Scientific Games Corporation.
 * Optilan — communications and security company. Established in 1990, its headquarters is in Coventry.
 * Optical Express Group (listed as DCM (Optical Holdings) Ltd; trading as Optical Express) — is a company that provides ophthalmology services such as laser eye surgery, cataract surgery, and lens replacement surgery. It is also a dispensing optician and operates a retail chain of clinics. Previously it operated a chain of dentists clinics, cosmetic clinics, and a private hospital. It is headquartered in Glasgow, Scotland. It was founded in 1991 by David Moulsdale. Its acquisitions include: Remocker Shapiro, Specialeyes plc, Co-op Eyecare, Specdeals, and The Health Clinic.
 * Opus Energy — is an energy company which supplies gas and electricity. Established in 2002, its headquarters is in Northampton. Formerly known as Oxford Power Holdings, since 2017 it is part of the Drax Group.
 * OVO Energy — energy company (electricity and gas supplier and home telecommunications). Established in 2009, its headquarters is in Bristol.
 * Oxford BioMedica — pharmaceuticals company (gene-based medicines). Established in 1995, its headquarters is in Oxford.
 * Oxford Instruments plc — is a designer and manufacturer of tools and systems for industry and research. Its inventions have included superconducting magnets, MRI whole body scanners, and active shielding for pacemakers. It is headquartered in Abingdon, Oxfordshire. It was founded in 1959 by Sir Martin Wood as the first substantial commercial spin-out company from the University of Oxford. In 2022 its revenue was £367 million, with a net income of £38 million.
 * Oxford Scientific Films — television and film production company. Established in 1968, its headquarters is in Oxford.
 * Oxitec — biotechnology company (genetically modified insect production for insect/disease control). Established in 2002, its headquarters is in Oxford.

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 * Pacific Horizon Investment Trust plc — is an investment trust focused on the Asia Pacific region (excluding Japan) and the Indian Sub-continent. It is headquartered in Edinburgh, Scotland. It was founded in 1989 as Dealchief plc before being given its present name in July of that year. Formerly managed by Tyndall International (Asia) Ltd, it is now managed by Baillie Gifford & Co Ltd.
 * PageGroup plc — is an international recruitment company headquartered in Weybridge, Surrey. It was founded in 1976 by Michael Page and Bill McGregor. In 1983 it was listed on the Unlisted Securities Market as Michael Page International. In 1988 it was floated on the London Stock Exchange. It was acquired by Spherion Corporation in 1997, and then, in 2001, it was demerged. In 2012 it was renamed as PageGroup. Its brands are Michael Page, Page Executive, Page Personnel, and Page Outsourcing. In 2022 its revenue was £1.9 billion, with a net income of £139 million.
 * Panorama Antennas — is a manufacturing company (communications antennas and closely related diplexer products). Established in 1947, its headquarters is in London. It was formerly known as J.F.J. Products.
 * Pantheon International — is a private equity fund of funds investment trust. It was founded in 1987, and is managed by Pantheon Ventures.
 * Paragon Banking Group plc — is a financial services company offering mortgages, savings accounts, and business finance. It is headquartered in Solihull, West Midlands. It was founded in 1985 as the National Home Loans Corporation. In 1997 it was renamed the Paragon Group of Companies. In 2003 it acquired Brittanic Money. It launched the internet bank Paragon Bank in 2014. In 2017 it was renamed Paragon Banking Group plc. It acquired Titlestone Property Finance in 2018. In 2022 its revenue was £393 million, with a net income of £313 million.
 * Parcelforce Worldwide — is a courier and logistics services company. Headquartered in Milton Keynes, Buckinghamshire; its parent company is Royal Mail. Its roots are in the Parcel Post service of Royal Mail which began in 1883. In 1990 Royal Mail Parcels was rebranded as Parcelforce, and in 1992 it was privatised.
 * Partridge Films (aka Partridge Productions) — is a television and film production company. Established in 1974, its headquarters is in Bristol.
 * Passion Pictures — is a film production company. Established in 1987, its headquarters is in London.
 * PD Ports — is a ports, shipping, and logistics company (formerly coal mining and engineering). It is the owner of Teesport, and ports at Hartlepool, Howden and Keadby; with additional operations at the Port of Felixstowe, Port of Immingham, and Port of Hull. Established in 1840, its headquarters is in Middlesbrough. It was formerly known as Powell Duffryn. Since 2009 it is owned by Brookfield Asset Management.
 * Pearson plc – is a British multinational publishing and education company headquartered in London. It owns Edexcel which is one of the examining boards for the UK. It also owns Pearson Vue which is an electronic education testing company. It produces textbooks and digital technology for teachers and children. Samuel Pearson founded the company in 1840 as a Yorkshire based construction business named S Pearson & Sons. The construction business ended in the 1920s with a move into publishing. Since then it has had interests in newspaper and book publishing, television broadcasting, software publishing, and data management, before concentrating on education services. In 2022 its revenue was £3.8 billion, with a net income of £244 million.
 * Pennon Group — is a utility company (water supply and sewage, waste management). Established in 1989, its headquarters is in Exeter, Devon. Its subsidiaries include South West Water and Viridor. In 2019 its revenue was £1.4 billion, with net income of £222 million.
 * Penrith Building Society — is a building society offering mortgages, savings, and insurance. Based in Penrith, Cumbria; it was founded in 1877.
 * Percy Main Productions — is the former name of Scott Free Productions a film and television production company.
 * Pershing Square Holdings Ltd — is a British investment trust that makes long-term investments in North American companies, tracking the performance of Pershing Square Capital Management. Founded in 2012, it is headquartered in Saint Peter Port, Guernsey.
 * Persimmon plc — is a housebuilding company headquartered in York, North Yorkshire. It was founded in 1972 by Duncan Davidson. Its acquisitions include Ideal Homes, the Scottish housing business of John Laing Group, Tilbury Douglas Homes, Beazer Homes UK, Charles Church, and Westbury. Its brands include Persimmons Homes, Charles Church, and Westbury Partnerships. In 2022 its revenue was £3.8 billion, with a net income of £561 million.
 * Personal Assets Trust plc — is an investment trust headquartered in Edinburgh, Scotland. It was founded in 1983.
 * Pets at Home plc — is a pet supplies retailer selling small pets, and pet products such as food, toys, bedding, medication, and accessories. It also provides grooming, veterinary care, and dog training services. It is headquartered in Handforth, Cheshire. It was founded in 1991 by Anthony Preston. In 1999 it acquired Petsmart UK. In 2010 Pets at Home was acquired by Bridgepoint Capital who in 2010 sold it to Kohlberg Kravis Roberts. In 2014 it was floated on the London Stock Exchange. It owns Vets for Pets. In 2022 its revenue was £1.3 billion, with a net income of £124 million.
 * Pfizer UK — is a pharmaceuticals company. Established in 1952, its headquarters is in Tadworth, Surrey. It is a subsidiary of Pfizer.
 * Phoenix Group Holdings plc — is an insurance company headquartered in London. It was founded in 1857 as The Pearl Loan Company. In 1914 it was renamed The Pearl Assurance Company and later as Pearl Group. In 2008 it acquired Resolution Life including its Phoenix Assurance business. In 2010 it was renamed Phoenix Group Holdings. In 2018 it acquired Standard Life Assurance, and in 2021 it acquired the Standard Life brand. It also owns SunLife. In 2022 its revenue was £6.3 billion, with a net income loss of £1.7 billion.
 * Phoenix Natural Gas — is an energy company (gas supplier). Established in 1996, its headquarters is in Belfast, Northern Ireland. It was formerly part of British Gas.
 * Phones 4u — was a telecommunications company (mobile phone retailer) from 1987 to 2014. Headquartered in Newcastle-under-Lyme, Staffordshire, it was formerly known as Midlands Mobile Sales.
 * Photoplay Productions — is a film company (production, and restoration), established in 1990.
 * Picturehouse Cinemas — is a cinema chain, and film distribution company. Established in 1989, its headquarters is in London.
 * Pinball London — is a film production company. Established in 2009, its headquarters is in London.
 * Pinewood Group — is a film and television studios company. Established in 2001, its headquarters is in Iver Heath, Buckinghamshire.
 * Pinewood Studios — is a film and television studios. Established in 1936, it is located at Iver Heath, Buckinghamshire.
 * PizzaExpress (Restaurants) Ltd  (trading as PizzaExpress) — is a company that operates a multinational pizza restaurant chain. It is headquartered in Uxbridge, London. It was founded in 1965 by Peter Boizot. In 1993 it was acquired by Hugh Osmond and Luke Johnson who floated it on the London Stock Exchange that year. In 2003 it was acquired by TDR Capital and Capricorn Associates who took it private again. In 2005 it was floated on the LSE again as part of Gondola Holdings. In 2007 it was acquired by Cinven; by Hony Capital in 2015; and then by its bond holders in 2020. It is now a private company limited by shares. It also operates under the brands Milano, Marzano, and Za.
 * Plamil Foods — is a manufacturer of vegan food and drink products. It is headquartered in Folkestone, Kent. It was founded in 1956 by Leslie Cross, the then Vice-President of The Vegan Society, as the Plantmilk Society. In 1965 it was incorporated as Plantmilk Ltd, and in 1972 renamed Plamil Foods.
 * Platform Home Loans — is a financial services company (mortgages). Established in 1989 as part of Bear Stearns Home Loans, in 2009 it became part of The Co-operative Group.
 * Platform Post-production — is a film and television post production company. Established in 2001, its headquarters is in London.
 * Pockit — is a financial services company offering pre-paid spending cards, current accounts, and other finance products. Headquartered in London; it was founded in 2014 by Virraj Jatania.
 * Poison Pen Films — is a film production company, headquartered in Leeds.
 * Polar Capital Technology Trust — is an investment trust that invests in technology companies. Headquartered in London, it was established in 1996.
 * PolyGram Filmed Entertainment — was a film production company from 1980 to 2000. It was formerly known as PolyGram Films, PolyGram Pictures, and as PFE.
 * Porcelain Film — is a film and television production company. Established in 2004, its headquarters is in London.
 * Porterbrook Leasing Company Ltd — is a railway company (leasing of rolling stock and associated equipment). Established in 1994, it was formed as part of the privatisation of British Rail.
 * Portland Communications — is a communications company (political consultancy, and public relations). Established in 2001, its headquarters is in London.
 * Portobello Post — is a film company (video and film post production), headquartered in London.
 * Portsmouth Water — is a utility company (water supply). Established in 1857, its headquarters is in Portsmouth, Hampshire.
 * Poundland — is a company that operates a discount general merchandise store chain. It is headquartered in Willenhall, West Midlands. It was founded in 1990 by Dave Dodd and father and son Keith and Steven Smith. In 2002 it was acquired by Advent International; in 2010 by Warburg Pincus; then in 2016 by Steinhoff International. Its acquisitions include 99p Stores, and Frozen Value Ltd (which had operated as Fulton's Foods). Its subsidiary is Dealz.
 * Poundstretcher — is a company that operates a discount general merchandise store chain. It is headquartered in Kirby Muxloe, Leicestershire. It was founded in 1981 by Paul Appell and Stephen Fearnley. In 1989 it became a subsidiary of Brown & Jackson plc. In 2003 a rebranding of the stores to '... instore' was begun. This was halted in 2009 when the company was acquired by Crown Crest Group which is owned by brothers Rashid and Aziz Tayub. Its subsidiaries are Bargain Buys and Poundstretcher Extra.
 * Poundworld — was a company that operated a discount general merchandise store chain. It was headquartered in Normanton, West Yorkshire. It was founded in 1974 by father and son Chris Edwards Sr and Chris Edwards Jr. Formerly named 'Bargain Centre', and then 'Everything £1', it was renamed 'Poundworld' in 2003. In 2013 it introduced the store chain Bargain Buys which was originally named 'Discount UK'. In 2015 a majority stake in Poundland was acquired by TPG Capital. In 2018 it became defunct.
 * Powell and Pressburger — was a film production company from 1939 to 1957. It was also known as The Archers, and as Archers Film Productions.
 * Powell Duffryn — is the former name of PD Ports, a sea ports company.
 * Premier — is a symbol group company with retail outlets that are mainly convenience stores. As well as branded products it offers own-brand ranges such as Euro Shopper and Happy Shopper. Some stores have in-store post offices. It is headquartered in Wellingborough, Northamptonshire. It was founded in 1994. Its parent company is Booker Group which is owned by Tesco plc.
 * Premier Foods – is a food manufacturing public company that owns brands such as Mr Kipling, Ambrosia, Bird's Custard, Angel Delight, Oxo, Bisto, Batchelors and also produces Cadbury cakes under license. It was founded in 1975 as Hillsdown Holdings by Harry Solomon and David Thompson. First located in London, it is now headquartered in St. Albans, Hertfordshire. In 2020 its revenue was £847 million, with a net income of £46.5 million.
 * Premier Inn — is a hospitality company operating a hotel chain. Established in 1987, its headquarters is in Dunstable, Bedfordshire. It was formerly known as Travel Inn. Its parent company is Whitbread.
 * Primerdesign — is a biotechnology company (products for quantitative real-time polymerase chain reaction). Established in 2005, its headquarters is in Southampton.
 * PricewaterhouseCoopers — is a multinational professional services network that is the second largest in the world. It is headquartered in London. It was founded in 1998, when Coopers & Lybrand merged with Price Waterhouse.
 * Principality Building Society (Cymdeithas Adeiladu'r Principality) – is the largest building society in Wales by assets. Offering mortgages, savings, investments, and insurance; it is headquartered in Cardiff, Wales. It was founded in 1860 as the Principality Permanent Benefit Building Society, and incorporated in 1876 as the Principality Permanent Building Society. In 1913 it was renamed the Principality Building Society. It has been merged with Bridgend Building Society in 1959; Urban Building Society in 1962; Maesteg Permanent Benefit Society in 1968, Aberavon Mutual Permanent Building Society, and Swansea & Carmarthen Building Society in 1974; Llanelli Permanent Building Society in 1977; District Building Society in 1978; Gorseinon Building Society in 1979; and Chatham Building Society in 1985. Its subsidiaries include Nemo Personal Finance Ltd.
 * Progressive Building Society — is a building society offering mortgages, savings, and investments. Headquartered in Belfast, Northern Ireland; it was founded in 1914. It was merged with the City of Derry Building Society in 2014.
 * Prudential plc — is a multinational financial services company (life assurance, pensions and investment). Established in 1848, its headquarters is in London. It owns Prudential Corporation Asia, and Jackson National Life. In 2019, its revenue was £93.7 billion, with total income of £792 million.
 * Publicity Pictures — was a film production company from 1925 to 1945. It was headquartered in London.
 * PureGym Ltd — is a company that operates a multinational health club chain. It is headquartered in Leeds, West Yorkshire. It was founded in 2009 by Peter Roberts. It was owned by CCMP Capital and other investors until it was acquired by Leonard Green & Partners in 2017. Its acquisitions include: the UK operations of LA Fitness, Fitness World, and basefit.ch.

Q

 * QA — is a digital education and skills provider offering virtual and classroom training, higher education, apprenticeships and talent solutions. Established in 1983, its headquarters is in London.
 * QinetiQ Group plc — is a multinational defence technology company operating in the defence, security, and critical national infrastructure sectors as well as the commercial sector. It is headquartered in Farnborough, Hampshire. Founded in 2001; its assets were previously part of the Defence Evaluation and Research Agency. It was privatised and floated on the London Stock Exchange in 2006. It has made a number of acquisitions in the UK, US, and continental Europe. The QinetiQ Group is composed of QinetiQ EMEA (Europe, Middle East, and Australasia), and QinetiQ North America. In 2022 its revenue was £1.3 billion, with a net income of £90 million.
 * Quantum Pharmaceutical — is a pharmaceuticals company producing and supplying unlicensed medicines, and special obtain products). Established in 2004, its headquarters is in Burnopfield, County Durham. In 2021 it was acquired by Target Healthcare with support from N4 Advisory.
 * Quantum Sports Cars — is a manufacturer of sports cars. Established in 1967, its headquarters is in Devon.
 * Quick Off The Mark Productions — was a film and television production company that operated from 2009 to 2016. It was headquartered in Glasgow, Scotland.
 * Quiz Clothing (trading as Quiz; part of Tarak International Ltd) — is a company that operates a clothing retail store chain, and retail website. It was founded in 1993 and is headquartered in Glasgow, Scotland.
 * Qwerty Films — is a film production company that was established in 1999.

R

 * Radical Sportscars – is a racing car manufacturer. Established in 1997, its headquarters is in Peterborough.
 * Randox Laboratories — is a biotechnology company providing in-vitro diagnostic reagents, and equipment for laboratory medicine. Established in 1982, its headquarters is in Crumlin, County Antrim, Northern Ireland.
 * Rathbones Group plc — is a financial services company offering investment management, wealth management, tax planning, pension advice, and banking services. It is headquartered in London. It was founded in 1742 by William Rathbone II as a Liverpool based timber trading business. In the 19th century it traded in cotton, and in 1841 became the Liverpool agent of the East India Company. In 1912 it stopped its trading operations and moved into financial services. In 1988 it was merged with Comprehensive Financial Services Ltd to form Rathbone Brothers before its name was changed to Rathbone Group in 2021. In 2022 its revenue was £435 million, with a net income of £49 million.
 * R. Durtnell & Sons — was a house building, restoration, and renovation company. It was headquartered in Brasted, Kent. It was founded in 1591 as a Durtnell family business and remained so until it became defunct in 2019.
 * Reckitt — is a multinational consumer goods company. Established in 1999 by the merger of British company Reckitt & Colman plc and Dutch company Benckiser N.V, its headquarters is in Slough, England.
 * Recorded Picture Company — is a film production company. Established in 1974, its headquarters is in London.
 * Redbus Film Distribution — was a film production and distribution company. See Lionsgate UK.
 * Redde Northgate plc — is a commercial vehicle rental company that operates in the UK and Spain. It is headquartered in Darlington, County Durham. It was founded in 1897 as Goode Durrant & Murray. In 1987 it was acquired by Ariadne Australia who renamed it Goode Durrant plc. Later that year Goode Durrant acquired Northgate Motor Holdings. In 1999 it was renamed Northgate plc. In 2020 it was merged with Redde plc to form Redde Northgate plc. In 2022 its revenue was £1.2 billion, with a net income of £101 million.
 * Redrow plc — is a house building company with 14 operational divisions across the UK. It is headquartered in Ewloe, Flintshire, Wales. It was founded in 1974 by Steve Morgan. Its acquisitions include: Whelmar Lancashire, Costain Homes, and Radleigh Homes. In 2022 its revenue was £2.1 billion, with a net income of £328 million.
 * Reeltime Pictures — is a film and television production company, established in 1984.
 * Reel Cinemas — is a cinema chain company. Established in 2001, it was formerly known as Curzon.
 * Regal Cinemas — was a cinema chain company.
 * Reigate Waterworks Company — utility company (water supply), 1859–1896. It became part of East Surrey Water Company.
 * Reliance Bank Ltd — is a bank offering mortgages, savings, and loans to The Salvation Army, individuals, charities, and businesses. Headquartered in London; it was founded in 1890 by William Booth as the Salvation Army Deposit Bank, and in 1891 was registered as the Salvation Army Bank. In 1901 it was renamed Reliance Bank Ltd. It is owned by The Salvation Army International Trustee Company, and the Salvation Army Trustee Company.
 * RELX plc — is a British multinational information and analytics company headquartered in London. It provides scientific, technical, and medical information and analytics, legal information and analytics, decision making tools, and organizes exhibitions. It is the world's largest publisher of academic articles and owns publications such as The Lancet and Cell. Previously named Reed Elsevier, it was founded in 1993 by the merger of Reed International, a British publisher, with Elsevier, a Netherlands based publisher. Its subsidiaries are Elsevier, LexisNexis, Reed Exhibitions, and LexisNexis Risk Solutions. In 2022 its revenue was £8.5 billion, with a net income of £1.6 billion.
 * Remus Films — was a film production company, 1954–1958.
 * ReNeuron — biotechnology company (stem cell therapies). Established in 1997, its headquarters is in Surrey.
 * Renishaw plc – is an engineering company whose products include coordinate-measuring machines, and machine tool products. It is headquartered in Wotton-under-Edge, Gloucestershire. It was founded in 1973 by Sir David McMurtry and John Deer. In 2022 its revenue was £671 million, with a net income of £120 million.
 * Rentokil Initial plc — is a business services company headquartered in Crawley, West Sussex. It was founded in 1925 by Harold Maxwell-Lefroy as a pest-control business. In 1957 it was acquired by British Ratin and became Rentokil Laboratories Ltd in 1960, and later renamed Rentokil Group. In 1996 it acquired BET plc becoming Rentokil Initial and offering a range of business services. Its brands include Rentokil, Initial, Steritech, Ambius, Terminix, and Western Exterminator. In 2022 its revenue was £3.7 billion, with a net income of £232 million.
 * Retirement Villages Group Ltd — is a developer and manager of retirement communities. Founded in 1981; it is headquartered in Leatherhead, Surrey. In 2017 it was acquired by Axa S.A..
 * Retrogenix — biotechnology company (human cell microarray screening services). Established in 2008, its headquarters is in Sheffield.
 * RHA Technologies Ltd. – Consumer electronics company (audio products). Established in 2008, its headquarters is in Glasgow, Scotland.
 * Richard Evans and Company — was a coal mining company that operated from 1730 to 1899.
 * Richer Sounds — is a company that operates a retail store chain and retail website offering hifi, home cinema, and television products. It is headquartered in London. It was founded in 1978 by Julian Richer with the help of Vic Odden. In 2019 Richer stated that he had transferred company ownership to the employees by passing 60% of his shares to an employee ownership trust.
 * Richwater Films — was a film production and distribution company that operated from 2013 to 2016. It was headquartered in London.
 * Rightmove plc — is a real estate company that runs an online real estate property portal. Headquartered in London, it was founded in 2000. In 2022 its revenue was £332 million, with a net income of £195 million.
 * Rio Tinto — mining company (Anglo–Australian multinational metals and mining corporation). Established in 1873, its headquarters are in London, UK and Melbourne, Australia. In 2019 its revenue was £43.1 billion, with net income of £6.9 billion.
 * RIT Capital Partners plc — is an investment trust headquartered in Spencer House, Westminster, London. It was formerly the Rothschild Investment Trust and was founded in 1961 for investments by the English branch of the Rothschild family.
 * River Island — is a company that produces and sells clothing and accessories for women, men, and children, and beauty products. It operates a multinational retail store chain, and a retail website. It is headquartered in London. It was founded in 1948 by Bernard Lewis, and the Lewis family still owns the company through the Lewis Trust Group. It was previously named 'Lewis Separates', and then 'Chelsea Girl' from 1965 to 1988 when it was renamed 'River Island'.
 * Riversimple — manufacturing company (automobiles). Established in Ludlow, its headquarters is in Llandrindod Wells, Wales.
 * RJB Mining — mining company (coal). See UK Coal.
 * Robin Hood Energy — state owned non-profit energy supplier (gas and electricity). Established in 2015, its headquarters is in Nottingham. It is owned by Nottingham City Council.
 * Rocket Pictures — film and television production company. Established in 1996, its headquarters is in London.
 * Rogue Films — film and television production company. Established in 1974, its headquarters is in London. It was formerly known as Drum Films.
 * Rolls-Royce Holdings — is a holding company that owns Rolls-Royce, a British multinational engineering company that manufactures civil and military aero engines, marine propulsion systems, power generation equipment, and formerly luxury automobiles. Established in 2011, it is headquartered in London, and has 9 subsidiaries. It was formerly Rolls-Royce plc, and Rolls-Royce Group plc. In 2019 its revenue was £16.5 billion, with net income of £1.3 billion.
 * Rolls-Royce Limited — was a manufacturing company (aerospace and automobile designer and manufacturer). Established in 1904 in Manchester, it was later headquartered in Derby. It was nationalised in 1971 until 1987 when it was privatised as Rolls-Royce plc.
 * Rolls-Royce Motor Cars — is a manufacturing company (luxury automobiles). It is a subsidiary of BMW. Established in 1998, it is headquartered in Goodwood, West Sussex.
 * Rolls-Royce Motors — was a manufacturing company (luxury automobiles), 1973–1998. It was formerly part of Rolls-Royce Limited. It was acquired by Vickers in 1980, and sold to BMW in 1997.
 * Romulus Films — film production company from 1948, then medicine production from 2013. It was established in 1948.
 * Rotork plc — is a manufacturer of industrial flow control equipment including valve actuators, gearboxes, control systems, instrumentation, and accessories. It is headquartered in Bath, Somerset. It was founded in the 1940s. In 1968 it was floated on the London Stock Exchange. In 2022 its revenue was £641 million, with a net income of £93 million.
 * Roxy Palace — was an online gambling company. Established in 2002, its headquarters is in London.
 * Royal Bank of Scotland (RBS) — financial services company (banking and insurance). Established in 1727, its headquarters is in Edinburgh, Scotland. In 1969, it merged with the National Commercial Bank of Scotland to form the National and Commercial Banking Group, which was later renamed the Royal Bank of Scotland Group and then NatWest Group. Its immediate parent company is NatWest Holdings, the "ring-fenced" business of NatWest Group.
 * Royal Mail — British multinational postal service and courier company. Established in 1516 as a government department, its headquarters is in London.
 * RS Group plc — is a distributor of industrial and electronics products and services headquartered in London. It was founded in 1937 by JH Warring and PM Sebestyen as Radiospares. In 1967 it was renamed Electrocomponents plc, until 2022 when it was renamed RS Group plc. Its brands include RS, RS Americas, Inc, and OKdo. In 2022 its revenue was £2.5 billion, with a net income of £230 million.
 * Ruffels Pictures — was a film distribution company in the silent film era.
 * Ruffer Investment Company Ltd — is an investment company focused on internationally listed equities and securities. Founded in 1994; it is headquartered in London.

S

 * Safestore Holdings plc — is a self-storage company that operates storage sites. It is headquartered in Borehamwood, Hertfordshire. It was founded in 1998. In 2013 it was converted into a real estate investment trust. Its acquisitions include Mentmore plc, and Space Maker. In 2022 its revenue was £212 million, with a net income of £462 million.
 * Saffron Building Society — is a building society offering mortgages, savings, investments, loans, and insurance. It is headquartered in Saffron Walden, Essex. It was founded in 1849 by the Revd. John Marten as the Saffron Walden Second Building Society. In 1968 it took over The Saffron Walden and Essex Mechanics Permanent Building Society. In 1972 it took over the Royston & District Building Society to become the Saffron Walden & District Building Society. In 1979 it merged with the London and Essex Building Society to become the Saffron Walden & Essex Building Society. In 1989 it merged with the Herts & Essex Building Society to become the Saffron Walden, Herts & Essex Building Society. In 2006 it was renamed the Saffron Building Society.
 * Sage Group plc — is a British multinational enterprise software company headquartered in Newcastle upon Tyne. It was founded in 1981 by David Goldman, Paul Milford Muller, and Graham Wylie. Its subsidiaries include Sage Intacct. In 2022 its revenue was £1.9 billion, with a net income of £260 million.
 * Sainsbury's (J Sainsbury plc) — is a company that operates supermarkets, convenience stores, banking services, catalogue retailer (Argos), and household furnishings retailer (Habitat)). Established in 1869, its headquarters is in Holborn, London. In 2019 its revenue was £29 billion, with a net income of £219 million.
 * Sainsbury's Bank — is a financial services company. Established in 1997, its headquarters are in Edinburgh, Scotland, and London. It was first established as a joint venture between J Sainsbury plc and Bank of Scotland, then in 2014 Sainsbury's took full ownership.
 * Saint John d'El Rey Mining Company — was a mining company with gold mining interests in Brazil). It operated from 1830 to 1985, and was headquartered in London. For a period it used slave labour.
 * Salts Healthcare Ltd — is a manufacturing company producing ostomy and orthotic products, and formerly also surgeon's instruments and surgical appliances. Established in the 1700s in Wolverhampton, its headquarters is in Aston, Birmingham.
 * Samvo Group – was a gambling company that operated from 2004 to 2017. It was headquartered in London.
 * Sands Films — is a film production company. Established in 1975, its headquarters is in London.
 * Sandscale Mining Company — was a mining company. Established in 1877, it is now defunct.
 * Santander UK plc — is a financial services company offering mortgages, savings, and investments. Established in 2010, its headquarters is in Euston, London. It was formed by the merger of Abbey National with Bradford & Bingley and 3 months later with the Alliance & Leicester. Its parent company is Santander Group. In 2018 its revenue was £5.4 billion, with a net income of £1.3 billion.
 * Savers Health & Beauty Ltd (trading as Savers) — is a company that operates a discount retail store chain and retail website offering health, beauty, household goods, and medical products. It is headquartered in Dunstable, Bedfordshire. It was founded in 1988 and expanded through the 1990s including the acquisition of the Supersave retail store chain. In 2000 it was acquired by A.S. Watson Group which is owned by CK Hutchison Holdings. A.S. Watson also owns Superdrug Stores plc and converted many Savers stores to Superdrug stores.
 * Savills plc — is an estate agent, and real estate services company. It is headquartered in London. It was founded in 1855 by Alfred Savill. In 1997 it was merged with First Pacific Davies in Asia. In 1998 it bought majority stakes in the German, French, and Spanish operations of Weatherall, Green & Smith. Its acquisitions include Smiths Gore, GBR Phoenix Beard, Larry Smith Italia, and Aguirre Newman SA. In 2022 its revenue was £2.2 billion, with a net income of £119 million.
 * Schroder AsiaPacific Fund plc — is an investment trust focused on Asia and Pacific bordering countries (excluding the Middle East, Japan, and Australasia). It was founded in 1995 and is managed by Schroders.
 * Schroder Oriental Income Fund plc — is an investment trust focused on the Asia Pacific region. Founded in 2005; it is managed by Schroders.
 * Schroders — is a British multinational asset management company (previously also banking). Established in 1804, its headquarters is in London. In 2019 its revenue was £2.5 billion, with net income of £495 million.
 * Schuh — is a company that operates a footwear retail store chain, and a retail website. It also has its own footwear brand. It is headquartered in Livingston, Scotland. It was founded in 1981 by Sandy Alexander. In 1986 it was acquired by Goldbergs. In 1990 it was the subject of a management buy-out which formed Schuh Ltd. In 2011 it was acquired by Genesco.
 * Scott Cinemas — is a cinema chain company, headquartered in Newton Abbot, Devon.
 * Scott Free Productions — is a British-American film and television production company. Established in 1970, its headquarters is in London. It was formerly known as Scott Free Enterprises, and as Percy Main Productions.
 * Scottish American Investment Company plc — is an investment trust headquartered in Edinburgh, Scotland. It was founded in 1873 by William Menzies. It is managed by Baillie Gifford & Co.
 * Scottish Building Society — is a building society that provides banking and financial services. It is headquartered in Edinburgh, Scotland. It was founded in 1848 as the Edinburgh Property Investment Company. In 1929 it was renamed the Scottish Building Society. In 2013 it was merged with Century Building Society.
 * Scottish Hydro Electric — was an energy company generating and supplying electricity and gas. It operated from 1989 to 1998. Headquartered in Perth, Scotland, it was formed from the North of Scotland Hydro-Electric Board. It was acquired by SSE plc in 1998.
 * Scottish Mortgage Investment Trust — is a financial services company providing investment management. Established in 1809, its headquarters is in Edinburgh, Scotland. It was formerly known as the Straits Mortgage and Trust Company. It is managed by Baillie Gifford & Co.
 * Scottish Nuclear — was an energy company providing electricity by nuclear power generation from 1990 to 1996. It was formerly part of the South of Scotland Electricity Board. It became part of British Energy and Magnox Electric.
 * Scottish Power — is an energy company generating, supplying, and distributing electricity. Established in 1990, its headquarters is in Glasgow, Scotland. It was formed mainly from the South of Scotland Electricity Board. Its parent company is Iberdrola.
 * Scottish Water — is a state owned utility company supplying water water and disposing of sewage. Established in 2002, its headquarters is in Dunfermline, Scotland. It was formed by a merger of West of Scotland Water Authority, East of Scotland Water Authority, and North of Scotland Water Authority. It is owned by the Scottish Government.
 * Screwfix Direct Ltd (trading as Screwfix) — is a company that operates a retail store chain, retail website, and mail order catalogue offering building trade tools, accessories, and hardware, DIY and home improvement products, and garden supplies. It is headquartered in Yeovil, Somerset. It was founded in 1979 by Jon Goddard-Watts as the Woodscrew Supply Company. In 1992 it was renamed 'Screwfix Direct'. In 1999 it was acquired by Kingfisher plc who remain its owners.
 * Seabrook Crisps Ltd – is a producer of crisps, headquartered in Bradford, West Yorkshire. It was founded in 1945 by Charles Brook in Allerton, West Yorkshire. Since October 2018 it is owned by Calbee UK. In 2017 it had a net income of £27 million.
 * Secure Trust Bank Ltd — is a bank offering savings, personal and business banking, and loan products such as motor finance, retail point of sale loans, commercial finance, real estate finance, asset finance, and invoice finance. Headquartered in Solihull, West Midlands; it was founded in 1952 as Secure Homes Ltd. In 1985 it was made a subsidiary of the Arbuthnot Banking Group. In 1994 it was renamed the Secure Trust Bank, and in 2011 it was floated on the London Stock Exchange.
 * See-Saw Films — is a British-Australian film and television production company. Established in 2008, its headquarters is in London.
 * SEEBOARD — was an energy company supplying electricity that operated from 1947 to 2002. It was formerly the South Eastern Electricity Board. In 2002 it became part of 24seven.
 * Segro plc — is a multinational property and investment company that develops and invests in business space, and industrial property. Established in 1920, its headquarters is in London. It was formerly known as Slough Trading Company Ltd, and as Slough Estates Ltd. In 2019 its revenue was £432 million, with net income of £860 million.
 * Selfridges Retail Ltd (trading as Selfridges and also known as Selfridges & Co) — is a company that operates four luxury department stores in London, Manchester and Birmingham, and a retail website. It is headquartered in Oxford Street, London. It was founded in 1908 by Harry Gordon Selfridge who opened the Selfridges, Oxford Street store in 1909. In 1926 Selfridge Provincial Stores was started which included a number of regional stores until it was sold to the John Lewis Partnership in 1940. In 1951 John Lewis acquired the remaining Oxford Street store and then added a store in Ilford, London that was later sold. In 1965 John Lewis including Selfridges was acquired by the Sears Group who opened an additional store in Oxford which was rebranded to John Lewis in 1986. In 1990 Selfridges was demerged from Sears and then a new store was opened at the Trafford Centre, Manchester. In 2002 another store was opened at Exchange Square, Manchester, and in 2003 a new store was opened at the Bull Ring, Birmingham. In 2003 Selfridges was acquired by Galen Weston and included in Selfridges Group which also contained Brown Thomas, Arnotts, Holt Renfrew and De Bijenkorf. In 2021 the majority of Selfridges Group was acquired by a joint venture between Central Group and Signa Holding.
 * SES Water — is a utility company supplying water. Established in 1996, its headquarters is in Redhill, Surrey. Formerly known as Sutton and East Surrey Water, it was formed from the merger of East Surrey Water and Sutton District Water.
 * Seven Arts Pictures — film production company. Established in 2002, it was later liquidated. It was headquartered in London.
 * Seven Cars Limited — manufacturing company (automobiles). See Caterham Cars.
 * Seven Seas — manufacturing company (vitamins, minerals and health and fitness supplements). Established in 1935 in Hull, its headquarters is in Feltham, London. Formerly known as British Cod Liver Oil Producers (BCOL), it was acquired by Imperial Tobacco in 1974, Hanson Trust in 1986, Merck Group in 1996, and Procter & Gamble in 2019.
 * Severn Trent — utility company (water). Established in 1989, its headquarters is in Coventry. It was preceded by Severn Trent Water Authority. In 2019 its revenue was £1.7 billion, with net income of £315 million.
 * Severn Trent Water Authority — state owned utility company (water), 1974–1989. Headquartered in Birmingham, it was preceded by Derwent Valley Water Board, and succeeded by Severn Trent.
 * SGN — energy company (gas supplier). Established in 2005, its headquarters is in Horley. It was formerly known as Scotia Gas Networks.
 * Shakerley Collieries — mining company (coal), c1850s–1935. It became part of Manchester Collieries.
 * Shawbrook Bank Ltd — is a bank offering savings, loans, and business finance. Headquartered in London; it was founded in 2011 when a group of investors acquired Whiteaway Laidlaw Bank from Manchester Building Society and rebranded it as Shawbrook Bank. Its parent company is Shawbrook Group plc which is owned by a consortium led by BC Partners and Pollen Street Capital.
 * Sheffield Coal Company — mining company (coal) 1805–1961. It was headquartered in Sheffield, South Yorkshire. In 1937 it was acquired by United Steel Companies, then became part of the National Coal Board in 1947, and became defunct in 1961.
 * Sheffield Film Cooperative — film and radio production company. Established in 1975, its headquarters is in Sheffield.
 * Shepherd Building Group Ltd — is a company that manufactures, leases, and sells modular buildings such as its Portakabin and Portaloo brands. It is headquartered in York, North Yorkshire. It was founded in 1890 by Frederick Shepherd and remains a Shepherd family business. It diversified from house building to general contracting and in 1934 was incorporated as F Shepherd & Son Ltd. During WWII it fulfilled government contracts. After the war until the 1950s its work was mainly in the public sector. In 1962 it was reorganised as Shepherd Group Ltd and was a main contractor in many industries. From the 1950s it introduced and manufactured a number of prefabricated, relocatable buildings such as Portasilo, and Portakabins. From 2015 it retained the Portakabin division but sold or closed the other divisions. In 2020 its revenue was £345 million, with a net income of £64 million.
 * Shepherd Neame Ltd — is a brewery headquartered in Faversham, Kent. It produces cask ales, and filtered beers. It also owns 305 pubs and hotels in South East England. Captain Richard Marsh founded it in 1698. Samuel Shepherd bought the brewery in 1741 and through a number of family generations expanded and modernised it. Percy Beale Neame joined the brewery in 1864 and five generations of his family have run the business with the latest being Jonathan Neame. Beers produced include Bishops Finger, and Spitfire. It also brews international lagers under license, distributes other alcoholic beverages, and collaborates with Sheppys to produce Orchard View Apple Cider.
 * Shepperton Studios — film studio. Established in 1931 at Shepperton, Surrey, it was first named Sound Film Producing and Recording Studios. It was also formerly known as Sound City. It is owned by the Pinewood Group.
 * Shine TV (UK) — Television production company. Established in 2001, its headquarters is in London.
 * Shire — pharmaceuticals company (drug development and production). Established in 1986 in Basingstoke, it moved its company registration to Ireland in 2008. It was acquired by Takeda Pharmaceutical Company in 2018.
 * Shoe Zone plc — is a company that operates a budget footwear store chain, and retail website. It is headquartered in Leicester, Leicestershire. It was founded in 1917, and formerly named Bensonshoe. Its acquisitions include: The Oliver Group plc, Shoefayre, Stead & Simpson, and others. In 2022 its revenue was £156 million, with a net income of £13 million.
 * SHS International — pharmaceuticals company (advanced medical nutrition products). Established in 1879 in Liverpool, it was formerly known as Powell & Scholefield. In 1990 it was acquired by Valio Oy, and then by Nutricia in 1995.
 * Sigma Films — film production company. Established in 1996, its headquarters is in Glasgow, Scotland.
 * Silver Vision — DVD and video distribution company. Owned by Clear Vision Ltd, it became defunct in 2014.
 * Siva Motor Car Company — was an automobile manufacturing company that operated from 1970 to 1976. It was headquartered in Aylesbury.
 * Sirhowy Valley Foods — is a snack food manufacturer. It was founded in 1997 as Real Crisps. In 2007 it was purchased by Tayto (Northern Ireland).
 * Sirius Minerals — mining company (mining of minerals, fertiliser development), established in 2003. In March 2020 it was acquired by Anglo American plc.
 * Skipton Building Society — is a building society offering mortgages, savings, and insurance. Headquartered in Skipton, North Yorkshire; it was founded in 1853. It acquired the Barnoldswick & District Permanent Building Society in 1942; the Ribblesdale Permanent Building Society in 1966, and the Bury Building Society in 1974. In 1996 it acquired the estate agents Connells Group. In 2009 it merged with the Scarborough Building Society, then the Chesham Building Society in 2010.
 * Sky Betting & Gaming — is an online gambling company. Established in 2002, its headquarters is in Leeds. It is owned by Flutter Entertainment.
 * Slater Menswear — also referred to as Slaters, is a company that operates a menswear store chain, and retail website. It is headquartered in Glasgow, Scotland. It was founded in 1904 by Samuel Slater and remains owned and run by the Slater family.
 * Smith & Nephew plc — is a multinational manufacturing company producing medical equipment products for advanced wound management, arthroscopy, trauma and clinical therapy, and orthopedic reconstruction. Established in 1856, its headquarters is in Watford, Hertfordshire. In 2019, its revenue was £5.1 billion, with net income of £600 million.
 * Smith Electric Vehicles — was a manufacturing company producing electric trucks, trams, milk floats, ice-cream floats, fork lifts, and taxis. It operated from 1920 to 2017. Originally headquartered in Washington, Tyne and Wear, its headquarters was moved to Kansas City, Missouri US. It was formerly known as Northern Coachbuilders (NCB).
 * Smiths Group plc — is an engineering company producing detection sensors, mechanical seals, couplings, hydrodynamic bearings, filtration systems, medical devices, electric components, heating and ducting systems; and previously timepieces, diamonds, automotive instrumentation and accessories, aerospace and marine instrumentation. Established in 1851, its headquarters is in London. It was formerly known as S. Smith & Sons, and as Smith Industries. In 2019 its revenue was £2.4 billion, with a net income of £227 million.
 * Smithson Investment Trust — is an investment trust headquartered in London. It was founded in 2010. In 2023 it has £43 billion worth of assets under management.
 * Snaffling Pig Ltd is a snack food company producing pork scratchings, and other snacks. Headquartered in Ashampstead Common, Berkshire, it was founded in 2013 as The Giggling Pig.
 * Society of Mines Royal — was a metals mining company that operated from 1568 to circa 1750. It was probably merged with the Company of Mineral and Battery Works in 1669.
 * Softcat plc — is an information technology infrastructure provider. It also created the Explain IT podcast. It is headquartered in Marlow, Buckinghamshire. It was founded in 1993 by Peter Kelly in High Wycombe as Software Catalogue. In 2022 its revenue was £1 billion, with a net income of £110 million.
 * Sofology Ltd — is a company that manufactures and sells furniture. It operates a furniture retail store chain and retail website. It is headquartered in Golborne, Greater Manchester. It was founded in 1974 as CLS Sofas. It was later renamed 'Clayton Salesrooms', 'CS Lounge Suites Ltd', 'Sofaworks', and finally 'Sofology' in 2016. In 2017 it was acquired by DFS Furniture plc.
 * Solocrest — automobile and motorbike manufacturer, see Ariel Motor Company
 * Somerfield — retail company (groceries), 1875–2011. Headquartered in Bristol and then Manchester, it was previously known as J.H. Mills, and Gateway Supermarkets. In 1988 it acquired Kwik Save before selling the brand in 2006. In 2009 it was purchased by The Co-operative Group and continued as a brand name until 2011.
 * Somerset Film — film production and training company. Established in 1997, its headquarters is in Bridgwater, Somerset.
 * Sound City — film studio. See Shepperton Studios.
 * Sound Film Producing and Recording Studios – film studio. See Shepperton Studios.
 * South Essex Waterworks Company — utility company (water supply), 1861–1970. In 1970 it merged with the Southend Waterworks Company to form the Essex Water Company.
 * South East Water — utility company (water supply). Established in 1992, its headquarters is in Snodland, Kent.
 * South of Scotland Electricity Board (SSEB) — energy company (state owned electricity generator and supplier), 1954–1991. In 1955 it absorbed the South West Scotland Electricity Board, and the South East Scotland Electricity Board. It became part of Scottish Nuclear and Scottish Power.
 * South Staffordshire Water — utility company (water supply). Established in 1853, its headquarters is in Walsall, West Midlands. It was formerly known as the South Staffordhire Waterworks Company.
 * South West Water — utility company (water supply and sewage). Established in 1989, its headquarters is in Exeter, Devon. It was preceded by the South West Water Authority. Its parent company is the Pennon Group.
 * Southend Waterworks Company — utility company (water supply), 1871–1970. In 1970 it merged with the South Essex Waterworks Company to form the Essex Water Company.
 * Southern Electric — energy supplier (electricity), 1970–1998. Headquartered in Reading, Berkshire, it was formed from the Southern Electricity Board. It was succeeded by Scottish and Southern Energy.
 * Southern Water — utility company (water supply and sewage). Established in 1989, its headquarters is in Worthing, West Sussex. It was preceded by the Southern Water Authority. Its parent company is Southern Water Capital.
 * Southwark and Vauxhall Waterworks Company — utility company (water), 1845–1903. Headquartered in London, it was formed from the merger of the Southwark, and Vauxhall water companies. It became part of the Metropolitan Water Board.
 * Spark Energy — energy company (electricity and gas supplier, telecoms), 2007–2018. Headquartered in Selkirk, Scottish Borders, it has become part of OVO Energy.
 * Spartoo UK is an e-commerce website specialising in shoes and clothing created in 2009 as part of the company Spartoo.com, created in 2006 and based in Grenoble, France.
 * Speakit Films — film production company, established in 2004.
 * Specsavers Optical Group Ltd (trading as Specsavers) — is an optometry company that operates a multinational retail chain of dispensing opticians clinics. It also sells hearing aids. Most of their clinics are joint venture partnerships, with the others operating as franchises. It is headquartered in Saint Andrew, Guernsey. It was founded in 1984 by married couple Doug Perkins and Mary Perkins. In 2004 it acquired the Blic Optic franchise.
 * Spectris plc — is a manufacturer of precision instrumentation, controls, and other engineering products. It is headquartered in London. It was founded in 1915 by Charles Richard Fairey as an aeroplane manufacturer named the Fairey Aviation Company. In the 1990s the company was re-focused on electronics products. In 2001 it was renamed Spectris plc. In 2022 its revenue was £1.3 billion, with a net income of £401 million.
 * Speymalt Whisky Distributors Ltd — is a producer of Scotch whisky and a bottling company. Trading as Gordon & MacPhail, it is headquartered in Elgin, Moray, Scotland. It was founded in 1895.
 * Spin TV — is a television production company. Established in 2007, its headquarters is in Soho, London.
 * Spirax-Sarco Engineering plc — is a manufacturing company that produces steam management systems, peristaltic pumps, and associated fluid path technologies. Established in 1888, its headquarters is in Cheltenham, Gloucestershire. It was formerly known as Sanders, Rehders & Co. (SARCO). In 2019 its revenue was £1.2 billion, with net income of £167 million.
 * Spire Healthcare Group plc — is a private healthcare company that operates hospitals, clinics, and GP surgeries. It is headquartered in London. It was founded in 2007 by the sale of Bupa hospitals to Cinven. It was floated on the London Stock Exchange in 2014. In 2022 its revenue was £1.1 billion, with a net income of £8.2 million.
 * Sportech — is a gambling company (online gambling). Established in 2000, its headquarters is in London.
 * Sports and Leisure Management Ltd (trading as Everyone Active) — is a company that manages over 200 leisure centres on behalf of local authorities and trusts. It also provides several public health services under the brand Everyone Health. Headquartered in Hinckley, Leicestershire; it was founded in 1987 by Stephen Hulme.
 * Spreadex — is a gambling company. Established in 1999 in Dunstable, its headquarters is in St Albans.
 * S Records – record label, see Syco Music
 * SSE plc — energy company (generator and supplier (electricity and gas), and telecoms networks). Established in 1998, its headquarters is in Perth, Scotland. It was formed from a merger of Scottish Hydro Electric and Southern Electric. It was formerly known as Scottish and Southern Energy. In 2019 its revenue was £7.3 billion, with net income of £1.4 billion.
 * SSL International — was a manufacturing company producing healthcare products. It operated from 1999 to 2010. Headquartered in London, it was formed by the merger of Seton Scholl and LIG. In 2010 it was acquired by and folded into Reckitt Benckiser.
 * SSP Group plc — is a multinational food service company that operates catering and retail units as well as fulfilling catering contracts. It is headquartered in London. It was founded in 1961 as a division of airline company SAS Group named SAS Catering. Its Select Services Partner (SSP) division was acquired by Compass Group in 1993. It was then acquired by EQT AB in 2006 and then floated on the London Stock Exchange in 2014. In 2022 its revenue was £2.1 billion, with a net income of £9.9 million.
 * St. James's Place plc — is a financial services company providing wealth management. Established in 1991, its headquarters is in Cirencester, Gloucestershire. It was formerly known as J Rothschild Assurance Group. In 2019 its revenue was £16.5 billion, with net income of £187 million.
 * Stafford Railway Building Society — is a building society offering mortgages, savings, and investments. Headquartered in Stafford, Staffordshire; it was founded in 1877.
 * Stallergenes Greer — multinational pharmaceuticals company (immunotherapy). Established in 2015, its headquarters is in London. It was formed by the merger of Stallergenes and US Greer Laboratories.
 * Standard Bank Limited — financial services company (multinational banking company mainly operating in Africa), 1862–1969. Headquartered in London, it was formerly known as Standard Bank of British South Africa. In 1969 it was merged with Chartered Bank of India, Australia and China to form Standard Chartered Bank.
 * Standard Chartered plc — British multinational financial services company (universal bank, consumer and commercial banking). Established in 1969, its headquarters is in London. It was formed from the merger of Chartered Bank of India, Australia and China with Standard Bank Limited. In 2019 its revenue was $15.4 billion, with net income of $2.3 billion.
 * Stanley Leisure — gambling company. Established in the 1950s, its headquarters is in Belfast.
 * Stanleybet International — gambling company. Established in 1997, its headquarters is in Liverpool.
 * Starling Bank — is an online bank offering personal and business banking services such as current accounts, and loans. Headquartered in London; it was founded in 2014 by Anne Boden. Its acquisitions include: Fleet Mortgages, and the mortgage book of Masthaven. In 2023 its revenue was £453 million, with a net income of £142 million.
 * Staveley Coal and Iron Company — coal mining, iron works, and chemicals company, 1863–1960. Headquartered in Staveley, Derbyshire, it was also known as Staveley Iron and Chemical Company. In 1960 it was acquired by Stewarts & Lloyds and merged with Stanton Ironworks to become Stanton and Staveley which was nationalised into the British Steel Corporation in 1967.
 * Stephenson Clarke Shipping — shipping company (short sea bulk cargo), 1730–2012. Headquartered in Newcastle upon Tyne, it is the U.K.'s oldest shipping company.
 * Stevens Vehicles — manufacturing company (automobiles). Its headquarters is in Port Talbot, Wales.
 * SThree plc — is an international recruitment company specialising in the information technology, banking and finance, life sciences, engineering, and energy sectors. It is headquartered in London. It was founded in 1986 by Bill Bottriell and Simon Arber. In 2005 it was floated on the London Stock Exchange. Its brands include Computer Futures, Progressive, Real Staffing Group, and Huxley Associates. In 2022 its revenue was £1.6 billion, with a net income of £54 million.
 * Stolen Picture — film and television production company. Established in 2016, its headquarters is in London.
 * Stoll Film Studios — film studios. See Cricklewood Studios.
 * Stoll Pictures — film production and distribution company, established in 1918.
 * Strange Company — machinima production and distribution company, headquartered in Edinburgh, Scotland.
 * Suffolk Building Society — is a building society offering mortgages, savings, investments, and insurance. It is headquartered in Ipswich, Suffolk. It was founded in 1849 as the Ipswich & Suffolk Freehold Land Society, and later became the Ipswich and Suffolk Permanent Benefit Building Society, and then the Ipswich & Suffolk Building Society. In 1975 it merged with the Ipswich & District Building Society to become the Ipswich Building Society until 2020 when it was renamed the Suffolk Building Society.
 * Suited Caribou Media — film post-production company. Established in 2013, its headquarters is in Glasgow, Scotland. It was formerly known as Mr Q Media.
 * Superdrug Stores plc — is a company that operates a health and beauty products retail store chain and retail website. It also provides pharmacy services, nurse clinics, its own products brand, and a mobile virtual network. It is headquartered in Croydon, London. It was founded in 1964 by brothers Ronald Goldstein and Peter Goldstein as Leading Supermarkets Ltd before being renamed Superdrug later that year. In 1987 it was acquired by Woolworth Holdings which would later become Kingfisher plc. In 1988 it acquired Tip-Top retailers, and Share Drug Stores plc. In 2001 it was acquired by Kruidvat which was later acquired by A.S. Watson Group which is owned by CK Hutchison Holdings. A.S. Watsons also owns Savers and they converted 300 Savers stores to Superdrug stores while converting some of Superdrugs smaller stores to Savers.
 * Superdry plc — is a company that operates a clothing retail store chain, and a retail website. It also has its own clothing brand. It is headquartered in Cheltenham, Gloucestershire. It was founded in 2003 by Julian Dunkerton and James Holder. It was floated on the London Stock Exchange in 2010. In 2018 Supergroup plc was renamed Superdry plc.
 * Sutton District Water — utility company (water supply), 1863–1996. Headquartered in Sutton, London, it was formerly known as Sutton and Cheam Water Company. In 1996 it was merged with East Surrey Water Company to become Sutton and East Surrey Water.
 * Swansea Building Society (Cymdeithas Adeiladu'r Abertawe) — is a building society offering mortgages, savings, and loans. Headquartered in Swansea, Wales; it was founded in 1923.
 * SWEB Energy — energy supplier (electricity), 1990–2006. It was formed from the South Western Electricity Board. In 1999 it was acquired by EDF Energy.
 * Swizzels Matlow – is a confectionery manufacturer branded as Swizzels. Established by brothers Maurice and Alfred Matlow in 1928 in London, it is now based in New Mills, Derbyshire. In 2019 its revenue was £78.6 million, with a net income of £10 million.
 * Syco — entertainment company (music publishing, talent agency, film and television production) Headquartered in London, it is also known as Syco Entertainment. Its subsidiary is Syco Music, a record label established in 2002 in London, that was formerly known as S Records.
 * Sylva Autokits — manufacturing company (kit cars). Established in 1981, its headquarters is in Lincolnshire.
 * Syncopy Inc. — film production company. Established in 2001, its headquarters is in London.
 * Sweetapple — marketing and public relations company. Established in 2002, its headquarters is in London.

T

 * Tandem Money Ltd — operates Tandem Bank which is a digital bank with no branches. It offers savings, mortgages, and loans. Headquartered in Blackpool, Lancashire; it was founded in 2014 by Ricky Knox, Matt Cooper, and Michael Kent. Its acquisitions include: Harrods Bank, Pariti Technologies, Allium Lending Group, the mortgage book of Bank and Clients, Oplo, and Loop Money.
 * Tanfield Group — is an automobile manufacturing company (electric vehicles, and specialist engineering). Established in 2003, its headquarters is in Tyne and Wear. It was formerly known as Comeleon.
 * Tarmac Group — was a multinational building materials and construction company (building materials, road construction, maintenance subcontractors, housebuilding) that operated from 1903 to 2013. Headquartered in Wolverhampton, West Midlands, it was formerly known as the Tar Macadam Syndicate. In 2013 it was merged with the UK assets of Lafarge to form Lafarge Tarmac which became Tarmac plc.
 * Tarmac plc — is a building materials company. Established in 2013, its headquarters is in Solihull. It was formed from the merger of Tarmac Group with the UK assets of Lafarge. It was formerly known as Lafarge Tarmac. Its parent company is CRH plc.
 * Tata Steel Europe — steel production company. Established in 1999, its headquarters is in London. It was formerly known as Corus Group which was formed by the merger of British Steel plc and Koninklijke Hoogovens. Its parent company is Tata Steel.
 * Tate & Lyle plc — is a global supplier of food and beverage ingredients to industrial markets. It produces sweeteners such as sucralose, fructose, and allulose; texturants such as starch, and gums; health and wellness ingredients; and stabilisers and functional systems. It is headquartered in London. It was founded in 1921 by the merger of rival sugar refiner companies Henry Tate & Sons and Abram Lyle & Sons. It was a sugar refiner and producer of sugar based products such as Lyle's Golden Syrup. From the 1970s it began diversifying into commodity trading, transport, and engineering. In the 2000s it diversified into producing starches and other food ingredients, as well as biomaterials. In 2010 it sold its sugar refining business. It owns 50% of Primary Products Ingredients America LLC (Primient). In 2022 its revenue was £1.3 billion, with a net income of £236 million.
 * Tayto (Northern Ireland Ltd) — is a privately owned manufacturer of crisps and corn snacks, headquartered in Tandragee, County Armagh, Northern Ireland. It was founded in 1956.
 * Taylor Wimpey plc — construction company (housebuilding). Established in 2007, its headquarters is in High Wycombe, Buckinghamshire. It was formed from the merger of Taylor Woodrow and George Wimpey. In 2019 its revenue was £4.3 billion, with net income of £673 million.
 * Taylor Woodrow — was a multinational construction company (housebuilding, civil and commercial construction) that operated from 1921 to 2007. Headquartered in London, in 2007 it was merged with George Wimpey to form Taylor Wimpey plc.
 * Teachers Building Society — is a building society offering mortgages, savings, and insurance. It is headquartered in Wimborne, Dorset. It was founded in 1966 when the National Union of Teachers acquired the London Scottish Building Society in order to offer mortgages to teachers. It is still focused on the teaching profession, and the education sector.
 * Teddington Studios — film and television studios, 1910s—2014. It was located in London.
 * Telecom Plus — utility company (gas and electricity supply, landline and mobile telephony, and broadband). Established in 1996, its headquarters is in London. In 2019 its revenue was £804 million, with net income of £32 million.
 * Telford Homes plc — is a house building company that specialises in non-prime areas of London. It was founded in 2000. In 2019 it was acquired by CBRE Group's subsidiary Trammell Crow Company.
 * Tempean Films — film and television production company. Established in 1948, its headquarters is in London.
 * Temple Bar Investment Trust plc — is an investment trust focused on UK securities. It was founded in 1926.
 * Templeheart Films — film finance and production company, established in 2008.
 * Terra Firma Capital Partners — private equity company (with £4.7billion in assets). Established in 2002, its headquarters is in London. It was formerly part of Nomura Principal Finance Group.
 * Tesco Bank — financial services company (banking and insurance). Established in 1997, its headquarters is in Edinburgh, Scotland. It was formerly known as Tesco Personal Finance. Its parent company is Tesco plc.
 * Thames Water — is a utility company (water supply and sewage). Established in 1989, its headquarters is in Reading, Berkshire. It was formerly part of the Thames Water Authority and other publicly owned water companies. Its parent company is Kemble Water Holdings.
 * Thatchers Cider Company Ltd — is a cider producer based in Sandford, Somerset. It also processes blackcurrants. It was founded in 1904 by William Thatcher and is still owned and run by the Thatcher family.
 * Theatre Workshop Scotland — theatre and film production company. Established in 1965, it is located in Edinburgh, Scotland. It was formerly known as Theatre Workshop Edinburgh.
 * The Bank of London Group Ltd (trading as The Bank of London) — operates The Bank of London which is a clearing, correspondent, and wholesale bank in business in the UK, US, and Europe. It is headquartered in 100 Bishopsgate, City of London. It was founded by Anthony Watson, and launched in 2021.
 * The Bath & Racquets Club Ltd — operates the private members gym and squash club the Bath & Racquets Club, at Brook's Mews, Mayfair, London. It was founded in 1989 by Mark Birley who sold it together with his other Mayfair clubs to Richard Caring in 2007.
 * The Body Shop International Ltd (trading as The Body Shop) — is a company that produces cosmetics, skin care products, perfumes, bath products, and household products. It has a multinational retail store chain including both company owned stores, and franchises. It also has a retail website, and direct sales network. It is headquartered in London. It was founded in 1976 by Anita Roddick. In 1984 it was entered on London's Unlisted Securities Market before being floated on the London Stock Exchange. In 2006 it was acquired by L'Oréal who sold it to Natura & Co in 2017.
 * The Cambridge Building Society — is a building society offering mortgages, savings, and insurance. It is headquartered in Cambridge, Cambridgeshire. It was founded in 1850 as the Cambridgeshire Permanent Benefit Building Society. In 1945 it was renamed The Cambridge Building Society.
 * The Cumberland — is the trading name of Cumberland Building Society.
 * The Distillers Company — was a Scottish whiskey producer. It had previously manufactured pharmaceuticals, chemicals, and plastics. It operated from 1877 to 1986, with its headquarters in Edinburgh, Scotland, it was acquired by Guinness in 1986 to form United Distillers.
 * The Energy Group — was an energy company generating and distributing electricity and was also a gas supplier. It operated from 1990 to 1998. Headquartered in London, it was acquired by Texas Utilities.
 * The Entertainer (Amersham) Ltd (trading as The Entertainer) — is a toys retail store chain and retail website. It also owns the brands ToyZone, Gamleys, and Totally Toys. It is headquartered in Amersham, Buckinghamshire. It was founded in 1981 by married couple Catherine and Gary Grant. In 2019 it acquired Early Learning Centre. It is owned by Teal Group Holdings.
 * The GlenAllachie Distillers Company Ltd — is a producer of Scotch whisky that owns the GlenAllachie distillery in Aberlour, Scotland. It was founded in 2017.
 * The Gym Group plc — is a company that operates a health club chain. Headquartered in Croydon, London; it was founded in 2007 by John Treharne. In 2015 it was floated on the London Stock Exchange.
 * The Imaginarium (aka Imaginarium Productions) — is a film production and performance capture company. Established in 2011, its headquarters is in London.
 * The Light Cinemas — is a cinema chain company established in 2007.
 * The Melton Building Society (trading as Melton Building Society) — is a building society offering mortgages, savings, investments, and insurance. Headquartered in Melton Mowbray, Leicestershire; it was founded in 1875. It has a subsidiary named MBS Lending Ltd.
 * The Mill — film company (visual effects, and creative content). Established in 1990, its headquarters is in London. It is owned by Technicolor SA.
 * The Mob — is a television and commercials production company.
 * The Nottingham — is the trading name of the Nottingham Building Society.
 * The Oxford Artisan Distillery — distillery company. Established in 2017, its headquarters is in Oxford.
 * The People's Operator (TPO Mobile) — was a telecommunications company (mobile virtual network operator) from 2012 to 2019. It was headquartered in London.
 * The Perfume Shop — is a company that operates a perfume retail store chain and retail website. It is headquartered in High Wycombe, Buckinghamshire. Originally named EauZone; it was renamed The Perfume Shop in 1992. In 2005 it was acquired by A.S. Watson Group which is owned by CK Hutchison Holdings.
 * The Range (listed as C.D.S (Superstores International) Ltd) — is a company that operates a retail store chain and retail website offering a large number of products in the home, garden, and leisure categories such as homewares, furniture, curtains and blinds, diy, toys, art supplies, and more. It also produces products for its own brand. It is headquartered in Plymouth, Devon. It was founded in 1989 by Chris Dawson as C.D.S. Superstores. In 2023 it acquired Wilko's brand, website, and intellectual property, and later announced that it would open five Wilko branded stores.
 * The Rank Group — is a gambling company that operates casinos, bingo, and online gambling. It was formerly also operating as a film producer, cinema chain, engineering and leisure company. Established in 1995, its headquarters is in Maidenhead. In 2019 its revenue was £695.1 million, with net income of £27.6 million.
 * The Rank Organisation — was an entertainment company involved in film production and distribution, a cinema chain, and electrical manufacturing. It operated from 1937 to 1996, and was headquartered in London.
 * The Smith's Snackfood Company — is a British-Australian snack food company owned by PepsiCo. It was founded in 1920 in Cricklewood, London as Smith's Potato Crisps Ltd. The Australian subsidiary was founded in 1932 and is headquartered in Chatswood, New South Wales. In 1998 PepsiCo bought the company and removed most of the Smith's branding by moving most of Smith's products to the Walkers branding. The Australian division continues to use the Smith's branding as Smith's Chips.
 * The Tote — is a gambling company. Established in 1928, its headquarters is in Wigan.
 * the West Brom — is the trading name of the West Bromwich Building Society.
 * The Works.co.uk plc (trading as The Works) — is a company that operates a discount retail store chain and retail website offering books, arts and crafts products, gifts, toys, games, and stationery. It is headquartered in Coleshill, Warwickshire. It was founded in 1981 by Mike and Jane Crossley as 'Remainders Limited'.It entered administration in 2008 and was acquired by Endless LLP. In 2015 Dean Hoyle became majority shareholder and chairman. In 2018 it was floated on the London Stock Exchange.
 * The Unite Group plc (trading as Unite Students) — is a provider of purpose built student accommodation in the U.K. It was founded in 1991 by Nicholas Porter in Bristol where it is now headquartered. In 2022 its revenue was £259 million, with a net income of £356 million.
 * Thin Man Films — film production company. Established in 1988, its headquarters is in London.
 * Thorn EMI Screen Entertainment — film production, and distribution company. See EMI Films.
 * Thornton & Ross — pharmaceuticals company (medicines, disinfectant, health treatments), 1922–2013. Headquartered in Linthwaite, West Yorkshire, in 2013 it was acquired by Stada Arzneimettel.
 * Tide — fintech business company (banking). Established in 2015, its headquarters is in London.
 * Tiger Racing — automobile manufacturing company (kit cars). Established in 1989 in London, its headquarters is in Peterborough. It was formerly known as Tiger Cars.
 * Tigerlily Films — film and television production company, established in 2000.
 * Tigon British Film Productions (aka Tigon) — was a film production and distribution company. Established in 1966, its headquarters was in London.
 * Tilia Homes — is a house building company headquartered in Solihull, West Midlands. It was founded in 2021 when Kier Living (the housing division of the Kier Group) was acquired by Terra Firma Capital Partners.
 * Tipton & Coseley Building Society — is a building society offering mortgages, and savings. Headquartered in Tipton, West Midlands; it was founded in 1901.
 * Titanium Resources Group — holding company of mining, exploration and marketing companies in Sierra Leone. Its headquarters were in London and Freetown,  Sierra Leone. It became Sierra Rutile Limited in 2011.
 * TJ Morris Ltd — is a company that owns the discount store chain Home Bargains. It is headquartered in Liverpool, and was founded in 1976 by Tom Morris. In 2023 it acquired Quality Save.
 * tombola — is a gaming company. Established in 1999, its headquarters is in Sunderland.
 * Total Car Parks Ltd — is a company that operates car parks. It was established in 2008, and is headquartered in Colchester, Essex.
 * Total Fitness Health Clubs Ltd — is a company that operates a chain of health clubs. Headquartered in Wilmslow, Cheshire; it was founded in 1993 by Albert Gubay. In 2004 it was acquired by Legal & General who sold it to North Edge Capital in 2015.
 * Trainline plc — is a company that operates a digital railway and coach technology platform that sells train tickets and rail cards. It also provides travel information. It is headquartered in London. It was founded in 1997 by the Virgin Group. In 2004 it merged with Qjump. In 2022 its revenue was £188 million, with a net income loss of £11.9 million.
 * Travis Perkins plc — is a builders' merchant and home improvement retailer with a chain of stores. It is headquartered in Northampton, East Midlands. It was founded in 1988 by the merger of Travis & Arnold with Sandell Perkins. Its subsidiaries include Toolstation, Keyline, BSS, Benchmarx, and CCF. In 2022 its revenue was £4.9 billion, with a net income of £192 million.
 * Tredegar Iron and Coal Company — iron works and coal mining company, 1797–1946. It was formerly known as Sirhowy Iroworks. In 1946 it was nationalised into the National Coal Board.
 * Trespass — is a clothing brand and the trading name of Jacobs & Turner Ltd.
 * Triga Films — pornographic film production, est. 1997
 * Triking – automobile manufacturing company. Headquartered in Hingham, Norfolk, it was formerly known as Triking Cyclecars.
 * Tropic Skincare — is a company that designs, manufactures and sells vegan skincare, hair care, and cosmetics products. It operates a multi-level marketing system. It is headquartered in Croydon, London. It was founded in 2007 by Susie Ma as Tropic Pure Plant Skincare. After Ma competed in The Apprentice, Alan Sugar became a joint partner until 2023 when Ma bought his shares for full ownership.
 * TR Property Investment Trust plc — is an investment trust focused on the property sector. Headquartered in London, it was founded in 1905. It is managed by Thames River Capital LLP.
 * TUI AG — Anglo-German multinational travel, hospitality, and tourism company (travel agencies, hotels, airlines, cruise ships, and retail stores). Established in 1923, its headquarters are in Hanover, and Berlin, Germany. It was originally known as the Prussian Mine and Foundry Company. Its 2019 revenue was £18.9 billion, with net income of £531 million.
 * TUI Airways — airline company. Established in 1962, its headquarters is in Luton, Bedfordshire. It was formerly known as Britannia Airways and also as Thomsonfly. Its parent company is TUI AG.
 * Tunnock's – Thomas Tunnocks Ltd. is a private limited confectionery company producing biscuits and cakes. Established in 1890, its headquarters is in Uddingston, Glasgow, Scotland.
 * TVF Media — film and television production company. Established in 1983, its headquarters is in London.
 * TVR — automobile manufacturing company (sports cars). Established in 1946 in Blackpool, its headquarters is in Walliswood, Surrey. It was formerly known as Trevcar Motors, TVR Engineering, and Layton Sports Cars. Its sister companies are Grantura Engineering, Grantura Plastics, and TVR Parts.
 * Twickenham Studios — is a film and television studios. Established in 1913, it is located in London.
 * Two Cities Films — is a film production company that was established in 1937.
 * Tyldesley Coal Company — was a coal mining and brick works company that operated from 1870 to 1947. Headquartered in Tyldesley, in 1947 it was nationalised into the National Coal Board.
 * Tyman plc — is a manufacturer of building products. It is headquartered in London. It was founded in 1993 by Stephen Dean as a property services company named Dean & Bowes (Homes) Ltd. In 1999 the property services business was sold and the company became an investment business named Lupus Capital. From 2006 it acquired a number of building products companies and became a building products manufacturer. In 2013 it was renamed Tyman plc. In 2022 its revenue was £715 million, with a net income of £47 million.
 * Tyrrells — is a manufacturer of crisps and other snacks. It was founded in 2002 by William Chase in Leominster, Herefordshire. Since May 2018 it is owned by KP Snacks.

U

 * UK Coal — was a coal mining, gas production, and renewable energy company from 1974 to 2015. Headquartered in Harworth, Nottinghamshire, it was formerly RJB Mining. It was succeeded by Harworth Group, a land and property company.
 * UK Power Networks — is an energy company (electricity distribution). Established in 2010, its headquarters is in London. It was formerly part of EDF Energy Works.
 * Ulster Bank Ltd — is a financial services company (banking and insurance). Established in 1836, its headquarters is in Belfast, Northern Ireland. It was formerly known as the Ulster Banking Company. Its parent company is NatWest Holdings, the "ring-fenced" business of NatWest Group.
 * Umbro — is a sports equipment manufacturer based in Manchester. Established in 1924, since 2012 is a subsidiary of Iconix Brand Group.
 * United Biscuits – is a British multinational food manufacturer specialising in biscuits and other snackfood under brands such as McVitie's, Jacob's, Twiglets, and Carr's. It was established in 1948 by a merger of McVitie's & Price with MacFarlane Lang. Following a number of acquisitions and changes in ownership, in 2014 it was acquired by Yıldız Holding and is now a subsidiary of Pladis. Headquartered in London, its 2020 revenue was £867 million with a net income of £77 million.
 * United House Developments — is a property development and house building company headquartered in London. It is focused on the construction of social housing, urban re-generation, refurbishment, and public—private partnerships. It was reorganised as United House Group. In 2014 it merged its construction business, United House Ltd, with Bullock Construction to form United Living Group. Later in 2014, United House Developments became a separate development company.
 * United Living Group — is a construction, utilities, and property maintenance company. It is headquartered in Swanley, Kent. It was founded in 2014 from the merger of Bullock Construction with United House Ltd (the construction division of United House Group). In 2019 United Living merged with Fastflow Group, remaining as United Living Group.
 * United Steel Companies — was a steel making, engineering, and coal mining company from 1918 to 1967. It was nationalised in 1967.
 * United Utilities — is a utility company (water supply and sewage). Formerly it also supplied electricity. Established in 1995, its headquarters is in Warrington. It was founded by the merger of North West Water and NORWEB. Its 2019 revenue was £1.8 billion, with net income of £363 million.
 * Unite Students — is the trading name of The Unite Group plc which is a provider of purpose built student accommodation.
 * Unity Trust Bank plc — is a bank that offers specialist financial services to trade unions, charities, other not-for-profit organisations, and ethical businesses. Headquartered in Birmingham; it was founded in 1984 as Unity Trust Ltd. It is owned by individual trade unions and federations, and other investors. Until 2014 The Co-operative Bank had a 26% stake.
 * Unusuality Productions — is a film production company. Established in 2005, its headquarters is in London.

V

 * Vandyke Productions — film production company, 1947–1956.
 * Vauxhall Motors — automobile manufacturing company (cars, commercial vehicles; tanks and military lorries during WWII). Established in 1857 at Vauxhall, London, its headquarters is in Chalton, Bedfordshire. It was formerly known as Alex Wilson & Company, and also as Vauxhall Iron Works. In 1925 it was bought by GM Motors, then sold to Groupe PSA in 2017.
 * Veolia Water Central — utility company (water supply), 1994–2012. Headquartered in Hatfield, Hertfordshire, it was formed as Three Valleys Water from the merger of the Colne Valley, Rickmansworth, and Lee Valley water companies. In 2012 it was merged into Affinity Water.
 * Veolia Water East — utility company (water supply), 1989–2012. Headquartered in Manningtree, it was formerly known as Tendring Hundred Water Services. In 2012 it was merged into Affinity Water.
 * Veolia Water Southeast — utility company (water supply), 1848–2012. Headquartered in Folkestone, Kent, it was formerly known as Folkestone & Dover Water Services. In 2012 it was merged into Affinity Water.
 * Verity Films — documentary film production company. Established in 1940, its headquarters is in London.
 * Vernalis plc — pharmaceuticals company (prescription drugs), 2003–2018. Headquartered in Winnersh, Berkshire, it was formerly British Biotech. In 2018 it was acquired by Ligand Pharmaceuticals.
 * Vernon Building Society — is a building society offering mortgages, and savings. Headquartered in Stockport, Greater Manchester; it was founded in 1924.
 * Vertigo Films — is a film production and distribution company. Established in 2002, its headquarters is in London.
 * Vesuvius plc — is a materials technology company that manufactures products such as ceramics for steelmakers and foundries, and the glass and solar energy industries. It is headquartered in London. It was founded in 1704 by Isaac Cookson as a group of metal and glass businesses in Tyneside. In 1851 it expanded into lead manufacturing. In 1924 it was merged with Lock Lancaster and W.W. & R.Johnson & Sons to form Associated Lead Manufacturers which was floated on the London Stock Exchange in 1930. In 1966 it was renamed Lead Industries Group, and in 1982 renamed as Cookson Group. In 1987 it acquired the Vesuvius Crucible Company. In 2005 it was refocused on high technology products. In 2012 it was renamed Vesuvius plc, and the performance materials division was demerged to form Alent plc. In 2022 its revenue was £2 billion, with a net income of £188 million.
 * Victrex plc — is a manufacturer and supplier of high performance polymers for a number of industries including: aerospace, automotive, electronics, oil and gas, and medical. It is headquartered in Cleveleys, Lancashire. It was founded in 1993 as a management buy-out of the Peek polymer business of Imperial Chemical Industries (ICI). In 2022 its revenue was £341 million, with a net income of £75 million.
 * ViiV Healthcare — pharmaceuticals company (HIV drugs). Established in 2009, its headquarters is in Brentford. It is a subsidiary of GlaxoSmithKline (76.5%), Pfizer (13.5%), and Shionogi (10%).
 * Vince & Son — transport manufacturing company (coachbuilders, motor buses, ex-government vehicles). Established in 1868, its headquarters is in Ely, Cambridgeshire.
 * Virgin Active Ltd — is a company that operates a multinational chain of health clubs. Headquartered in London; it was founded in 1998 by Richard Branson and Matthew Bucknall. In 2015 80% of the company was sold to South African investment company Brait, owned by Christo Wiese.
 * Virgin Group — British multinational venture capital conglomerate. Founded in 1970, its headquarters is in London.
 * Virgin Cinemas — cinema chain company, 1995–2002.
 * Virgin Films — film production and distribution company, 1979–1986.
 * Virgin Games — online gambling company, established in 2003.
 * Virgin Media — telecommunications and mass-media company (digital television, broadband internet, fixed line telephony, mobile telephony). Established in 2006, its headquarters is in Hook, Hampshire. It was formerly known as NTL-Telewest. Since 2013 it is a subsidiary of Liberty Global.
 * Virgin Money UK — financial services company. It was formerly known as CYBG plc. Its 2019 revenue was £1.7 billion, with net income of £194 million.
 * Viridor — waste management, recycling and renewable energy company. Established in 1956, its headquarters is in Taunton, Somerset. It was formerly known as Harrison Western, and also as Haul Waste. Its parent company is Pennon Group.
 * Vision Express — is an optometry company that operates a multinational retail chain of dispensing opticians clinics. The clinics are either company-owned or joint venture partnerships. It is headquartered in Ruddington, Nottinghamshire, and was founded in 1988. In 1997 it was acquired by Grand Vision which is owned by EssilorLuxottica. Its acquisitions include: Batemans Opticians, Crown Eyeglass, Rayner & Keeler, Conlons Opticians, and Tesco opticians which became VE@Tesco.
 * Vistry Group plc — is a house-building company headquartered in Kings Hill, Kent. It was founded in 2019 by the merger of Bovis Homes and Galliford Try's housing businesses. In 2022 it acquired Countryside Partnerships. Its revenue in 2022 was £2.7 billion, with a net income of £204 million.
 * Vodafone Group — is a British multinational telecommunications company (including fixed line telephone, mobile phone, broadband, digital television, internet television, and IPTV). Established in 1991, it has headquarters in London and Newbury, Berkshire. It has 1 division (Vodafone Global Enterprise) and 41 subsidiaries. Its predecessors were Racal Telecom, and Racal Vodafone Holdings, with the Vodafone brand introduced in 1985. Vodafone Group has also traded as Vodafone Airtouch. Its 2019 revenue was €43.6 billion, with net income of –€7.6 billion.
 * Volution Group plc — is a manufacturer of ventilation equipment for commercial and residential customers. It is headquartered in Crawley, West Sussex. It was founded in 2002 when HSBC Private Equity acquired the Air Movement and Cable Management business of Smiths Group plc. In 2006 it was acquired by ABN AMRO, and then by TowerBrook Capital Partners in 2012. Its brands include Vent-Axia. In 2022 its revenue was £307 million, with a net income of £35 million.
 * Vue Cinemas — cinema chain company. Established in 2003, its headquarters is in Chiswick, London.

W

 * Waitrose & Partners — is a supermarket chain founded in 1904 as Waite, Rose & Taylor. It was purchased in 1937 by the John Lewis Partnership and is now headquartered in Bracknell, Berkshire, and Victoria, London. In 2022 its total revenue was £6.9 billion, with an operating income of £1.02 billion.
 * Wales & West Utilities — is an energy company (gas supplier). Established in 2005, its headquarters is in Newport, Wales. It was formerly part of National Grid plc. It is owned by CK Infrastructure Holdings.
 * Walkers – is a snack food manufacturer whose products include crisps and other savoury snacks. It was founded in 1948 in Leicester by Henry Walker. In 1989 Walkers was acquired by Frito-Lay, a division of PepsiCo.
 * Walkers Shortbread – is a Scottish manufacturing company that mainly produces biscuits such as shortbread, cookies, and crackers. It was founded in 1898 in Torphins, Scotland by Joseph Walker. Still owned and managed by the Walker family, its headquarters is in Aberlour, Scotland.
 * Walthamstow Studios — was a film studios company from 1914 to 1930. Its headquarters was in Walthamstow, London.
 * Walturdaw Company Limited — was a film production, distribution, and film equipment company from 1901/4 to 1925. Its headquarters was in London.
 * Warburtons – is a private baking company that is the best selling bakery brand in the United Kingdom. It was established in 1876 by Thomas Warburton and is headquartered in Bolton, Greater Manchester.
 * Warp Films — is a film and TV production company. Established in 2001, its headquarters are in Sheffield and London. See also Warp X.
 * Warp Records — is a record label. Established in 1989, its headquarters was in Sheffield, and then London.
 * Warp X — is a film production company (sister company of Warp Films). Established in 2005, its headquarters was in Sheffield, then Notts, and then London.
 * Warwick Films — film productioncompany, 1951–1962. Its headquarters was in London.
 * Warwick Trading Company — film production and distribution company, 1898–1915. Its headquarters was in London.
 * Watches of Switzerland Group plc — is a retailer of Swiss watches that operates a chain of stores. It is headquartered in Braunstone Town, Leicestershire. It was founded in 1924 in Ludgate Hill, London. In 1988 it was acquired by Ratner Group and then sold to Asprey in the early 1990s. In 1998 it was the subject of a management buyout, and then acquired by Baugur Group in 2005. It was then bought by Landsbanki in 2009 before coming under the control of Apollo Global Management in 2013. It was briefly known as Aurum Holdings. In 2022 its revenue was £1.2 billion, with a net income of £101 million.
 * Water Plus — water retail company (water supply and sewage for businesses). Established in 2016, its headquarters is in Stoke-on-Trent. It is a joint venture between United Utilities and Severn Trent Water.
 * Waterstones Booksellers Ltd (trading as Waterstones) — is a company that operates a book shop chain, and a retail website. It also sells stationery, and has an instore cafe chain branded 'Cafe W'. It is headquartered in Piccadilly, London. It was founded in 1982 by Tim Waterstone. In 1993 it was acquired by WHSmith. In 1998 it was acquired by HMV Media plc (later HMV Group) which also acquired Dillons and Ottakar's and merged them into Waterstones. In 2011 it was acquired by A&NN Capital Fund Management owned by Alexander Mamut. In 2018 Elliott Management Corporation bought a majority stake in Waterstones. As well as Dillons, and Ottakar's its acquisitions include: Books Etc, Blackwell's, Hatchards, Hodges Figgis, and Foyles.
 * Weir Group plc — is a Scottish multinational engineering company headquartered in Glasgow. It was founded in 1871 by brothers George and John Weir as G & J Weir Ltd, manufacturing pumping equipment. In World War I it manufactured munitions, aircraft, and war materiel. In later years it diversified into the oil and gas industry and mining. In 2022 its total revenue was £2.4 billion, with a net income of £213 million.
 * Well Pharmacy — retail and pharmaceutical company (retail, pharmaceuticals, healthcare, and beauty products). Established in 1945, its headquarters is in Manchester. It was formerly The Co-operative Pharmacy, part of The Co-operative Group until, in 2014, it was sold to the Bestway Group.
 * Welsh-Pearson — film production and distribution company. Established in 1918, its headquarters is in London.
 * Welsh Water — non-profit utility company (water supply and sewage). Previously it was also an electricity supplier under the name Hyder. Established in 1989, its headquarters is in Nelson, Wales. It was preceded by the Welsh Water Authority. Its parent company is Glas Cymru.
 * Welsh National Water Development Authority — state owned utility company (water supply and sewage), 1973–1989. It was later known as the Welsh Water Authority. It was succeeded by Welsh Water.
 * Welwyn Studios — film studio company, 1928–1950. It was located in Welwyn Garden City, Hertfordshire.
 * Wessex Water — utility company (water supply and sewage). Established in 1973, its headquarters is in Bath, Somerset. It was formerly known as the Wessex Water Authority. Its parent company is YTL Corporation.
 * Westbourne Communications — public relations company.
 * West Bromwich Building Society (trading as 'the West Brom') — is a building society offering mortgages, savings, banking, investments, and insurance. It is headquartered in West Bromwich, West Midlands. It was founded in 1849 as the West Bromwich Permanent Building Society.
 * Westbury — was a house building company headquartered in Cheltenham, Gloucestershire. It was founded by the Joiner family in 1964. It was floated on the London Stock Exchange in 1986. Its acquisitions included Clarke Homes, Maunders, and Prowting. It diversified into prefabricated housing, and financial services. In 2005 it was acquired by Persimmon plc.
 * Western Power Distribution — energy company (electricity distribution). Established in 1999, its headquarters is in Bristol. It is composed of 3 companies – WPD South West, WPD South Wales, and WPD Midlands. Its parent company is PPL.
 * Westfield Sportscars — automobile manufacturing company (sports cars). Established in 1982, its headquarters is in Kingswinford, West Midlands.
 * West Middlesex Waterworks Company — utility company (water), 1806–1903. Headquartered in London, it became part of the Metropolitan Water Board.
 * Wetherspoons – is the trading name of J.D. Wetherspoon plc which operates a chain of pubs, bars, and hotels.
 * Whitbread — multinational hotel and restaurant company. It was formerly a brewery company and owner of an estate of licensed public houses. Established in 1742, its headquarters is in Houghton Regis, Bedfordshire. It was formerly known as the Hind Brewery. In 2023 its revenue was £2.6 billion, with a net income of £278 million.
 * Whitby Seafoods Ltd — is a food company that produces frozen seafood. It is headquartered in Whitby, North Yorkshire. It was founded in 1985 when Graham Whittle bought the defunct Whitby Shellfish Company.
 * White Crane Films, film production company. Established in 1990, its headquarters is in London.
 * White Stuff — is a company that produces women's, men's, and children's clothing, accessories, homeware and gifts. It operates a clothing stores chain, a retail website, and mail order catalogues. It was founded in 1985 by George Treves and Sean Thomas as 'Boys from the White Stuff', white stuff referring to snow.
 * WH Smith plc — is a retail company that operates a chain of shops selling books, stationery, magazines, newspapers, entertainment products, and confectionery. It is headquartered in Swindon, Wiltshire. It was founded in 1792 by Henry Walton Smith and his wife Anna as a news vendor in London. Former operationas include a library service, travel agents, do-it-yourself, book publishing, music retail shops, toy shops, and television broadcasting. In 2022 its revenue was £1.4 billion, with a net income of £53 million.
 * Whyte & Mackay Ltd — is a producer of Scotch whiskies, liquors, and vodkas, headquartered in Glasgow, Scotland. It was established in 1882 by Charles Mackay and James Whyte. It has a US subsidiary named Whyte & Mackay Americas. Since 2014 it is owned by Alliance Global Group.
 * Wickes Group plc — is a home improvement and garden supplies retail chain company catering to domestic consumers and the building trade. It is headquartered in Watford, Hertfordshire. It was founded in 1854 by Henry Dunn Wickes in Michigan, US. In 1972 the Wickes Corporation in partnership with builders merchant Sankeys opened the first Wickes store in the UK, which was expanded into a retail chain. In 2000 it was acquired by Focus Do It All who sold it to Travis Perkins in 2004. In 2021 it was demerged and spunoff by Travis Perkins, and floated on the London Stock Exchange as Wickes Group plc.
 * Wigan Coal and Iron Company — was a coal mining, and iron works company. Established in 1865, it has become defunct.
 * Wilko — was a retail store chain company that sold homewares and household goods. It was headquartered in Worksop, Nottinghamshire. It was founded in 1930 by James Kemsey Wilkinson in Leicester as Wilkinson. In 2012 it was rebranded as Wilko. In 2023 it was put into administration and became defunct. The brand name was acquired by The Range.
 * William Grant & Sons Ltd — is an alcoholic drinks company producing Scotch whisky and other spirits that is headquartered in Bellshill, Scotland. It was established in 1887 by William Grant and is run by his descendants. Its brands include Glenfiddich, Monkey Shoulder, Hendrick's Gin, Drambuie, Grant's, Balvenie, Three Barrels, Gibson's Finest, Tullamore Dew, and Reyka. It also owns a 30% stake in Highland Distillers.
 * William Hill — is a gambling company. Established in 1934, its headquarters is in London. In 2019 its revenue was £1.58 billion, with net income of £27 million.
 * William Leech plc — was a house building company headquartered in Tyneside. It was founded in 1934 by William Leech. In 1985 it was acquired by Beazer.
 * Williams & Glyn's Bank — was a financial services company providing banking and insurance. It operated from 1970 to 1985. Headquartered in London, it was formed by the merger of Williams Deacon & Co with Glyn, Mills & Co. Its parent company was the National and Commercial Banking Group, which was later renamed Royal Bank of Scotland Group (now NatWest Group).
 * Willmott Dixon — is a construction company active in contracting, residential development, interior fit-out and refurbishment, and property support services. It is headquartered in Letchworth, Hertfordshire. It was founded in 1852 by John Willmott and since 2005 is led by Rick Willmott, the fifth generation of the family. In 2021 its revenue was £1.1 billion, with a net income of £11 million.
 * Wilson Bowden — was a house building and general construction company. It was headquartered in Coalville, Leicestershire. It was founded in 1961 by David Wilson and was substantially expanded in the 1980s and 1990s. In 1987 it was floated on the London Stock Exchange as the holding company for David Wilson Homes, and its commercial property subsidiary Wilson Bowden Properties. Its acquisitions included Trencherwood, and the housing business of Henry Boot plc. In 2007 Wilson Bowden was acquired by Barratt Developments plc.
 * Windsor Studios — film studios company. See Catford Studios.
 * Wimbledon Studios — film and television studios company. Formerly known as Merton Studios, it is located in Colliers Wood, London.
 * Witan Investment Trust plc — is an investment trust focused on global equity. It is headquartered in London. It was founded in 1909 to manage the estate of Alexander Henderson, 1st Baron Faringdon. It was floated on the London Stock Exchange in 1924. In 1932 it established Henderson Administration to manage its funds before selling its stake in Henderson in 1997.
 * Wolfburn distillery — is a producer of Scotch whisky located in Thurso, Scotland. Founded in 1821, it ceased production in the 1850s before being reopened in 2013.
 * Woodfall Film Productions — film production company. Established in 1958, its headquarters is in London.
 * Woolworths Group plc — was a company that owned the UK high street general merchandise retail chain 'Woolworths' and other companies such as Entertainment UK and Bertrams Books. It was headquartered in London. It was founded in 1909 in Liverpool as a division of the US F. W. Woolworth Company. In 1982 it was acquired by Paternoster Stores Ltd which would become Kingfisher plc. In 2001 it was demerged together with Kingfisher's other general merchandise businesses to form 'Woolworths Group' which was floated on the London Stock Exchange in 2003. In 2009 the stores business became defunct. Before closure it had 807 stores. Its brands had included 'Winfield', Ladybird children's clothing, 'WorthIt!' value range, Chad Valley toys, 'pick n' mix' sweets, and Embassy Records. A Woolworths.co.uk internet retailer operated from 2009 to 2015.
 * Working Title Films — film and television production company. Established in 1984, its headquarters is in London. Its subsidiaries are: WT2 Productions (film production); and WTTV (TV productions).
 * Workspace Group plc — is a real estate investment trust that lets office, industrial, and workshops space to small and medium sized enterprises. It is headquartered in London. It was founded in 1987 as London Industrial to dispose of the commercial property of the defunct Greater London Council. In 1997 it was renamed Workspace Group plc. It was converted to a real estate investment trust in 2007. In 2022 its revenue was £132 million, with a net income of £123 million.
 * World of Books Group Ltd (trading as Wob) — is an online retail and recycling company offering second-hand books, cds, dvds, blu-rays, and video games. It purchases these in bulk from charity shops and from its websites Ziffit, and Shopiago which also offers e-commerce services. Eighty percent of the books purchased are recycled. It is headquartered in Goring-by-Sea, West Sussex. It was founded in the 2000s by Simon Downes, Ben Maxfield, and Michael Laundon. In 2016 it was acquired by a fund of Bridges Fund Management who sold a majority stake to Livingbridge in 2021. That year it was rebranded Wob.
 * Worldwide Healthcare Trust — is an investment trust that invests in biotechnology, and healthcare companies. Headquartered in London, it was established in 1995. It was previously known as Finsbury Worldwide Pharmaceutical.
 * World Wide Pictures (UK) — film, television, and multimedia production company. Established in 1935, its headquarters is in London.
 * WPP plc — communications, advertising, and public relations company. Established in 1971, its headquarters is in London. In 2019 its revenue was £13.2 billion, with net income of £707 million.
 * WRc — research consultancy company (water, waste and the environment). Established in 1927 it was formerly known as the Water Pollution Research Board (WPRB), the Water Pollution Research Laboratory (WPRL), and the Water Research Centre.
 * Wren Kitchens Ltd — is a company that designs, manufactures, and sells fitted kitchens, and fitted bedrooms through a retail store chain, and retail website. It is headquartered in Barton-upon-Humber, Lincolnshire. It was founded in 2009.
 * Wrexham Water plc — was a utility company supplying water that operated from 1863 to 1997. It was formerly known as Wrexham Waterworks Company, and as the Wrexham and East Denbighshire Water Company. In 1997 it became part of Dee Valley Water.

X

 * Xchanging — is a business and technology services provider to the insurance industry. It is owned by DXC Technology. Established in 1999, its headquarters is in London.
 * Xtract Resources — is a metals, minerals, and mining company. Established in 2004, its headquarters is in London. It was previously known as Resmex, and as Xtract Energy.

Y

 * Yeast Culture — is a film and TV production company. Established in 1999, its headquarters is in Camden, London.
 * Yorkshire Building Society — is a building society offering financial services such as mortgages, savings, investments, and insurance. It owns the Chelsea Building Society, the Norwich and Peterborough Building Society, Accord Mortgages, and the savings business of Egg Banking. It is headquartered in Bradford, West Yorkshire. It was founded in 1864 as the Huddersfield Equitable Permanent Benefit Building Society. It expanded through a number of mergers such as with the Bradford Permanent Building Society in 1975 after which it became the Huddersfield & Bradford Building Society. In 1982 it merged with the West Yorkshire Building Society to become the Yorkshire Building Society. It merged with the Haywards Heath Building Society in 1992; the Gainsborough Building Society in 2001; the Barnsley Building Society in 2008; the Chelsea Building Society in 2010; and the Norwich and Peterborough Building Society in 2011.
 * Yorkshire Electricity — was an energy company supplying and distributing electricity that operated from 1948 to 1997. Its headquarters was in Leeds, Yorkshire. It was formerly the Yorkshire Electricity Board. In 1997 it was acquired by American Electric Power and Public Service Company of Colorado.
 * Yorkshire Water — is a utility company supplying water and disposing of sewage. Established in 1973, its headquarters is in Bradford, Yorkshire. It was formerly known as the Yorkshire Water Authority. Its parent company is the Kelda Group.

Z

 * Zeneca — was a British multinational pharmaceutical company specialising in oncology and heart drugs, that operated from 1993 to 1999. Headquartered in London; it was formerly part of Imperial Chemical Industries (ICI). In 1999 it merged with Astra AB to form AstraZeneca.
 * Zenith Productions — was a film and TV production company that operated from 1984–2005. Later known as Zenith Entertainment; its subsidiary was Blaze Television.
 * Zenos Cars — is an automobile manufacturing company producing sports cars. Established in 2012, its headquarters is in Wymondham, Norfolk.
 * Zipline Creative — was a film, TV, and radio production company. Established in 2008, its headquarters is in Risca, South Wales.
 * Zopa Bank Ltd — is an online bank offering savings, loans, and credit cards. Headquartered in Tooley Street, London; it was founded in 2005 as a peer-to-peer lending platform. It received a full banking licence in 2020 and ended its peer-to-peer business in 2021.