Between 1951 and 1953, London Transport purchased 700 examples of the AEC Regal MK4 fitted with Metro-Cammell bodywork to replace their pre-war single deck fleet. Classified RF and of very modern appearance when introduced, these models were fitted with a front-entrance together with stylish fully-fronted bodywork. Often to be found on the extremities of LTS operations, the first RF entered service on Green Line route 704 (Windsor – Turnbridge Wells) in October 1951. The last of the class were withdrawn as late as 1979.