The RMC origins date back to June 1957 when London Transport took delivery of CRL4, this fourth and final prototype Routemaster had an ECW body designed specifically for use on the Green Line network. The most notable outward difference affected the rear which was modified to allow the fitting of electrically operated platform doors. CRL4 entered service in October 1957 on route 721, after some early teething problems were sorted out the bus moved from Romford to High Wycombe where it took up duties on route 711. Public reaction to the bus was favourable resulting in London Transport ordering 68 Park Royal bodied vehicles in 1961, originally it was planned that these would be called the CR class (Coach Routemaster) however this was changed to RMC before the first one were delivered in 1962.The batch RMC1453 to 1520 were very similar to the prototype expect for the front layout which apart from twin headlamp's was to the then standard RM design. The first buses entered service on route 715 operated by Guildford Garage on August 29th 1962. The rest of the class quickly followed resulting in a total of 8 routes being converted to the type.CRL4's frontal area was eventually modified to match the production vehicles and the bus was classified RMC4 however it remained unique as only Routemaster not carry a Park Royal Vehicles built body.