Timeline of the 2023 Periodic Review of Westminster constituencies

This article covers the timeline of the most recent cycle of the process to redraw the constituency map for the House of Commons, namely the 2023 Periodic Review of Westminster constituencies. The new constituency borders came into law on 29 November 2023. For a summary of the outcome of the review, see 2023 Periodic Review of Westminster constituencies.

Summary
The process for periodic reviews of parliamentary constituencies in the United Kingdom is governed by the Parliamentary Constituencies Act 1986, as amended by the Parliamentary Voting System and Constituencies Act 2011 and subsequently by the Parliamentary Constituencies Act 2020. This review was the successor to the 2018 Periodic Review of Westminster constituencies, which was ultimately abandoned after it failed to pass into law. After abandonment of the previous reviews since 2015, the review is set to be the first review based on electoral registers drawn up using Individual Electoral Registration which Parliament approved from 2014–15, an anti-fraud and personally empowering system in place in most of the world, replacing household registration condemned by the worldwide Office for Democratic Institutions and Human Rights (OSCE/ODIHR). By every, routine, local government canvass reaching slightly fewer imminent attainers of the age of 18 effectively than the old system of household registration a small group of LSE experts have blogged, this change very marginally favours the Conservatives. Local election offices are funded to implement mitigating measures to minimise any such disproportionate impacts. The Command Papers were sponsored and ordered by a Deputy Prime Minister, Nick Clegg, a Liberal Democrat.

Under current legislation, the four Boundary Commissions of the United Kingdom were required to report on their next review of the boundaries of parliamentary constituencies before 1 July 2023. In order to meet this deadline, the Commissions began their work on 5 January 2021. Following three rounds of public consultation, all four Commissions submitted their final proposals to the Speaker of the House of Commons on 27 June 2023. The Speaker immediately laid these before Parliament and the reports were published on the respective Commissions' websites the following day. The new boundaries were formally introduced into UK law on 15 November 2023 through The Parliamentary Constituencies Order 2023. (The original deadline of the end of October was missed by the government, which, according to the Act, must only happen in exceptional circumstances).

Previous reviews
The 2013 Periodic Review of Westminster constituencies was launched by the Parliamentary Voting System and Constituencies Act 2011. The process began in 2011 and was intended to be completed by 2013, but a January 2013 vote in the House of Commons temporarily stopped the process. The 2018 Periodic Review of Westminster constituencies commenced following the 2015 general election and the four Boundary Commissions submitted their final recommendations to the Secretary of State on 5 September 2018 and made their reports public a week later. Leader of the House of Commons Andrea Leadsom told the House on 13 September 2018 that "it will be some time" before the necessary statutory instruments would be put forward for approval by both the Commons and the Lords. The proposals were never put forward for approval before the calling of the general election held on 12 December 2019, and in December 2020 the reviews were formally abandoned under the Schedule to the Parliamentary Constituencies Act 2020.

Proposed changes
The Government's policy position regarding the process for the 2023 review was confirmed in a written statement, entitled Strengthening Democracy, by Minister of State for the Cabinet Office Chloe Smith on 24 March 2020. Smith confirmed in her written statement that primary legislation would be brought forward to remove the legal requirement to give effect to the recommendations of the Sixth Review and set the framework for future boundary reviews.

The main proposals in the statement were as follows:


 * Maintaining 650 seats
 * Under the legislation which governed the unimplemented 2018 Boundary Review recommendations, the number of constituencies was to be reduced from 650 to 600. It was proposed that this be retained at 650, on the grounds that Parliament had a greater workload following the UK's departure from the European Union.


 * Electoral quota tolerance
 * It was proposed to maintain the current tolerance of ±5% from the average size of constituencies (the "electoral quota").


 * Protected constituencies
 * It was initially proposed that there would be no change to the four protected constituencies of Isle of Wight (divided into two seats), Na h-Eileanan an Iar (the Western Isles of Scotland) and Orkney and Shetland (the Northern Isles of Scotland), which are protected from the electoral quota due to their unique geography. However, during the passage of the legislation, an amendment was introduced to add Ynys Môn (the Isle of Anglesey in Wales), increasing the number of protected constituencies to five.


 * Boundary review cycle
 * It was proposed that reviews be carried out every eight years, rather than the pre-2020 requirement of five years.


 * Implementation of recommendations
 * Under the law as it existed prior to 2020, the final proposals of the Boundary Commissions were brought into effect through an Order in Council that had to be approved by Parliament. It was proposed that the Order in Council should no longer require parliamentary approval.

Legislation
A bill was introduced on 19 May 2020 to reflect the written statement and it received its Second Reading on 2 June 2020. The Parliamentary Constituencies Act 2020 received royal assent on 14 December 2020. The Act amends the regulations underpinning the boundary review process, including the Parliamentary Constituencies Act 1986, Northern Ireland Act 1998, Boundary Commissions Act 1992 and Parliamentary Voting System and Constituencies Act 2011.

Commencement of reviews
The four Boundary Commissions formally launched their 2023 reviews on 5 January 2021, to coincide with the release by the Office for National Statistics (ONS) of electorate data from analysis of the electoral registers that had been published on 2 March 2020. The commissions jointly calculated the relevant electoral quota/range to be used for the 2023 review and the allocation of parliamentary constituencies between the four nations. The English commission further divided its allocation between the nine regions of England.

Size of constituencies
The electorate of the United Kingdom, comprising 650 constituencies, as determined by the ONS, was 47,558,398 on 2 March 2020. The electorate of the five protected constituencies – Isle of Wight (two seats), Na h-Eileanan an Iar, Orkney and Shetland, and Ynys Môn – amounted to 220,132, leaving 47,338,266 to be distributed between the remaining 645 constituencies, which gave an electoral quota of 73,393. Each non-protected constituency must have an electorate which is within 5% of this quota, which gave a permitted range of 69,724 to 77,062. In Northern Ireland the legislation allows for a wider range, in certain prescribed circumstances, from 68,313 to 77,062.

Of the 646 unprotected constituencies (Isle of Wight currently has only one seat), 236 had electorates within the permitted range, while 203 were below and 207 were above.

The regional distribution of these seats is shown in the following table.

United Kingdom
The 650 constituencies were allocated between the four nations of the UK in accordance with the method of allocation specified by the legislation as shown in the table below.

Regions of England
The Commission for England applied the same distribution formula to the English allocation, which results in the following redistribution of constituencies among the English regions: * Excluding Isle of Wight

Comparison with the Fifth Review
The current constituency boundaries were largely based on the Fifth Periodic Review of Westminster Constituencies which was carried out by the Boundary Commissions between 2000 and 2007. The Scottish review was completed in time for the 2005 general election, with the other three reviews coming into effect at the 2010 general election. In England, the fifth review was based on the number of electors on the electoral register published in February 2000. The electorates were therefore already 10 years out of date by the time it came into effect, and over 20 years had elapsed between the publication of that register and the start of the 2023 reviews.

The table below shows the movements in the national/regional electorates since those used for the fifth review.

Prospective wards
The detailed constituency and ward electorates issued by the ONS were based on the local authority boundaries which were currently effective and did not take account of prospective changes which were to be enacted on 1 December 2020. There were 31 such local authorities in England, of which 16 were London boroughs. The Commission for England subsequently worked with local authorities to produce updated data which included these 'prospective' wards. A comprehensive list of ward electorates was published on 24 March 2021.

Timetable
The initial outline timetable published by the Commission for England was as follows:


 * 5 January 2021: Begin development of initial proposals.
 * 10 May 2021: Publish Guide to the 2023 Review.
 * 8 June 2021: Publish initial proposals and conduct eight-week written consultation.
 * 22 February 2022: Publish responses to initial proposals and conduct six-week 'secondary consultation', including between two and five public hearings in each region.
 * 8 November 2022: Publish revised proposals and conduct four-week written consultation.
 * 27 June 2023: Submit and publish final report and recommendations.
 * 15 November 2023: Order in Council approved by King Charles III in the Privy Council; the order formally implemented the new boundaries by giving them force of law. (The original deadline of the end of October was missed by the government, which, according to the Act, must only happen in exceptional circumstances).

England
The Boundary Commission for England published their initial proposals on 8 June 2021. The proposals represent significant changes to the existing boundaries, with just 47 existing constituencies remaining unchanged (just under 10% of existing constituencies ). In addition, a further 69 constituencies were unchanged except to realign boundaries with new or prospective local government ward boundaries. Due to the constraints on the size of constituency electorates, it was not always possible to allocate whole numbers of constituencies to individual counties and to avoid crossing county boundaries. Accordingly, each region was divided into sub-regions which comprised a whole number of constituencies.

The information in the table below was primarily extracted from the commission's summary sheets for each region.

Northern Ireland
Initial proposals were published on 20 October 2021. As the number of constituencies in Northern Ireland remains the same, changes were only necessary to bring some of the electorates within the permitted range and align boundaries with those of revised local government wards. Belfast South would be enlarged into the countryside and renamed 'Belfast South and Mid Down'. East Antrim would be extended further west, while Fermanagh and South Tyrone would be extended further east into County Armagh.

Scotland
The Boundary Commission for Scotland released its initial proposals on 14 October 2021.

The following table details the proposed changes, based on the commission's press release.

Wales
Initial proposals for constituencies in Wales were published on 8 September 2021, reducing Wales' constituencies by 8, from 40 to 32.

Apart from the protected constituency of Ynys Môn, no constituencies were unchanged. The table below summarises the relationship between the remaining current constituencies and the initial proposals. Notes:

1 The proposed constituency of Bridgend contained the majority of the current constituency of Ogmore and a minority of the current constituency of Bridgend (including the town of Bridgend). The current constituency was effectively abolished, with the majority being included in the proposed constituency of Aberafon Porthcawl.

2 The proposed constituency of Vale of Glamorgan contained the majority of the existing constituency, but no part of any other constituency.

Political impact
According to analysis carried out in October 2021 by electoral modelling consultancy Electoral Calculus, a total of 28 constituencies would disappear (i.e. be broken up and not form the larger part of any proposed seats), offset by 28 wholly new constituencies (proposed seats which do not contain the larger part of any pre-existing seat). If the 2019 general election was re-run under the boundaries in the initial proposals, it was estimated that a further 23 seats would change hands. The overall effect would be a net gain of 13 seats for the Conservatives, a net loss of 8 for Labour, a loss of 3 for the Liberal Democrats and 2 for Plaid Cymru. This was further analysed as follows:

Consultation on initial proposals
The publication of the initial proposals by each of the Boundary Commissions was followed by eight-week consultation periods. In total, over 36,000 comments were received. The Commissions subsequently published these comments on their respective web sites and further six-week secondary consultation periods were then held, giving the opportunity for observations to be made on the comments made in the initial consultations. In addition, a total of 45 public hearings were conducted.

England
The Commission for England published revised proposals on 8 November 2022, followed by a third and final, four-week, consultation period ending on 5 December. After receiving over 45,000 comments over the previous two consultation periods, the Commission revised nearly half the proposed constituencies put forward in its initial review (including name changes). Of the 225 constituencies whose boundaries were revised, 90 have revised names. A further 34 constituencies changed names only. 55 of the 124 name changes reverted to the current constituency names, either because the revised constituency boundaries were more closely aligned with the current boundaries, or because local residents objected to the new names put forward by the commission. More extensive use of divided wards was included in the revised proposals, totalling 47, compared to 19 in the initial proposals. This enabled more communities to be kept together in one constituency and also meant that constituencies in some areas could more closely follow the existing configurations, resulting in fewer voters moving between seats.

The information in the table below was primarily extracted from the commission's summary sheets for each region.

Northern Ireland
The Commission for Northern Ireland published revised proposals for consultation on 14 November 2022.

Minor amendments were made to eight of the 18 constituencies, making more use of divided wards to minimise the changes necessary to the current configuration of constituencies. As a result of the revisions, the proposed name of the Strangford and Quoile constituency reverted to its current name of Strangford.

Scotland
The Commission for Scotland also published revised proposals for consultation from 8 November to 5 December 2022.

Of the 55 mainland constituencies, 20 were unchanged from the initial proposals, including three with changed names only. Of the 35 revised constituencies, 20 also have revised names. There were no changes to the proposed groupings of council areas, but only the Ayrshire and East Renfrewshire groupings were completely unaffected.

The final proposals were announced in June 2023.

Wales
The Commission for Wales published revised proposals on 19 October 2022, with comments due no later than 15 November.

The Commission revised its initial proposals in terms of their geographical make-up in 22 of the 32 allocated constituencies, and 9 of the proposed constituency names were amended. Most of the adjustments resulted from moving electoral wards between neighbouring constituencies. The most significant change was combining western parts of Newport with the majority of the existing constituency of Islwyn, rather than parts of Caerphilly, on the basis of better local ties, to form Newport West and Islwyn. The existing constituency of Caerphilly is retained with relatively minor changes composed wholly of wards of Caerphilly County Borough Council. There were also some boundary realignments in North Wales.

Political impact
Electoral Calculus count the revised proposals as being lessened. Namely four fewer very greatly changed seats (new and/or abolished) (24) and seven fewer seats changing hands, ceteris paribus (all votes cast being identical) (16 of the 650). Overall, compared to the initial proposals, this would map out to three fewer seats won by the Conservative party at the 2019 general election and three fewer lost by the Labour party, the supervening (wider swing in votes) meaning only a net gain of ten for the Conservatives and net loss of five Labour MPs. In November 2022, professors Colin Rallings and Michael Thrasher estimated the Conservatives would have won five additional seats in 2019, with Labour unchanged.

Final proposals
All four Commissions submitted their Final Recommendations Reports to the Speaker of the House of Commons on 27 June 2023 and they were immediately laid before Parliament. The reports were published on the respective Commissions' websites on 28 June 2023.

Changes from revised proposals
In England, after receiving a further 18,890 representations, 41 constituencies were revised, eight of which also involved a change of name. Most of these were relatively minor boundary changes between two neighbouring seats. In a further 45 constituencies, only the name was changed. This left 457 seats unaltered from the revised proposals published in November 2022. The final recommendations for England result in only 55 of the existing 533 constituencies remaining completely unchanged.

In Wales, 21 of the 32 seats were unaltered from the revised proposals; 10 had revised boundaries (of which five were renamed); and one had a name change only. In Scotland boundary changes affected 18 seats, of which 12 were renamed. Only name changes affected a further six, leaving 33 unaltered. In Northern Ireland, minor boundary changes affected five seats, with no changes to the proposed names.

Details relating to the final proposals are shown on 2023 Periodic Review of Westminster constituencies.

Parliamentary approval
In accordance with the Parliamentary Constituencies Act, the Order in Council to formally introduce the new boundaries into UK law should have been approved by 28 October 2023 – 4 months after the publication of the final reports, unless "there are exceptional circumstances". However, the Order was not given by the Privy Council until 15 November 2023, coming into effect on 29 November 2023.