The AEC Routemaster is a model of double-decker bus that was built by Associated Equipment Company (AEC) in 1954 (in production from 1958) and produced until 1968. Primarily front-engined, rear open-platform buses, a small number of variants were produced with doors and/or front entrances. Introduced by London Transport in 1956, the Routemaster saw continuous service in London until 2005, and currently remains on two heritage routes in central London. The Routemaster was developed by AEC in partnership with London Transport, the customer for nearly all new Routemasters, although small numbers were also delivered to the airline British European Airways (BEA) and the Northern General Transport Company. In all, 2,876 Routemasters were built, with approximately 1,000 still in existence.