London Buses route SL6

London Buses route SL6, formerly London Buses route X68, is a Transport for London contracted Superloop express bus route in London, England. Running between Russell Square and West Croydon bus station, it is operated by Go-Ahead London.

The route partially parallels routes 68 and 468.

The route runs towards Russell Square in the morning peak, and runs towards West Croydon bus station in the evening peak.

History
Route X68 commenced on 27 October 1986 as a peak-hour, express version of route 68 operating between Russell Square and West Croydon bus station with no stops made between West Norwood and Waterloo. It was operated by London Regional Transport's Norwood bus garage with Leyland Olympians fitted with high back seats. As part of the privatisation of London bus services, in January 1995 it was taken over by Arriva London.

Upon being re-tendered it passed to London Central on 3 April 2006 being operated by Wright Eclipse Gemini bodied Volvo B7TLs. Go-Ahead London successfully retained the route when re-tendered, commencing new contracts in 2011 and 2018, with Alexander Dennis Enviro400H MMCs introduced with the commencement of the latter contract. In 2018, a three-axle BCI bus was trialled on the route.

On 31 July 2023, route X68 was renumbered SL6, becoming part of the Superloop network of orbital express bus routes. Prior to being renumbered, the buses that operated route X68 also used to operate route 188, but when the buses were being reliveried, this crosslink ceased. After the morning services, the buses are taken to Waterloo garage, where they are cleaned for the evening services.

Current route
Route SL6 operates via these primary locations:
 * Russell Square
 * Holborn station
 * Aldwych
 * Waterloo Bridge
 * South Bank
 * Waterloo station
 * West Norwood station
 * Beulah Hill
 * Selhurst Park
 * West Croydon bus station