Finding a satisfactory British substitute for the German air compressor, bought from Bosch, was to cause problems for AEC once war broke out.

London Transport ordered 338 (later reduced to 150) chassis, which were in production when World War II broke out in September 1939.

The last of the batch, RT 151, did not reach London Transport until January 1942, six months after its predecessor, although all were built to full pre-war specification.

Production of the RT recommenced in late 1946, being delayed by London Transport's desire to have the bodies jig-built, following its experience building Halifax bombers at Aldenham Tube Depot (later to become its main bus works).

However, the London "RT" family of vehicles could be considered to have numbered 6,956 in total, consisting of 4,825 RTs; 1,631 RTLs and 500 RTWs.

In addition, some surplus bodies were, for a short time, put onto modified STL chassis and classed as SRTs.

In June 1953, RT3710, along with Leyland Titan RTL1459, was shipped to Switzerland and displayed at a trade fair in Zurich and a similar event in Malmö.

[6] In the 1963 British musical comedy film, Summer Holiday, Cliff Richard drives a converted RT bus to Athens.

Stunts involving the bus included a 360-degree spin, and slicing the top deck off on a low bridge to stop the pursuers.