Apart from two original prototypes, RML3 and CRL4, 575 Leyland 0.600 9.8 litre engines plus 6 spares were delivered to London Transport. RM632 had been delivered new in January 1961 with an AEC engine, but this was replaced with a Leyland unit before it entered service on 21 st June 1961. The first standard Routemaster delivered with a Leyland engine was RM870 in September 1961. Originally assigned to the Hanwell Garage, its performance was measured against the AEC-powered vehicles before being transferred to Cricklewood in April 1963.

The London General Omnibus Company was founded in 1855 to run the horse-drawn carriages in London . Following a merger in 1908 with the London Motor Omnibus Company, famous for its Vanguard buses, it was acquired two years later by the Underground Electric Railway Company of London Ltd. Manufacture of buses had started in Walthamstow in 1910, but in 1912, the manufacturing activity became the Associated Equipment Company (AEC) and the public transport operation continued under the name of London General. In 1933, all public transport was amalgamated under the newly-formed London Passenger Transport Board.To celebrate the 50 th anniversary of London Transport,in April 1983,

1983, London Transport celebrated its 50 th Anniversary by decorating four buses in special liveries. Titans T747, M57 and T66 were repainted in the old “General” livery but RM1983 was repainted all over in gold, the appropriate colour for a Golden Anniversary. It carried no advertising, just the slogan “We've been together now for 50 years” on both sides, and the special 50 th Anniversary logo in white. The gold RM1983 entered service on April 30 th at Thornton Heath Garage in the Croydon operating district,and then visited all eight operating districts.until it was repainted red in February 1984.

On December 9th 2005, the Routemaster finally disappeared from regular service in London, after more than 50 years of active service. Although several vehicles were in service that day, the officially designated “last” Routemaster was RM2217 which operated on Route 159 between Streatham and Marble Arch. Sun Star model 2914 replicates RM2217 exactly as it ran its last journey. A limited number of Routemasters continues to operate on so-called Heritage Routes as can be seen from the advertisements on RM2217.