This started in October 1935, with two more former LUT routes, and continued in stages until June 1940, when World War II caused the suspension of the programme.

In 1954, it was announced that all trolleybuses were to be replaced by diesel buses, with the exception of the post-war vehicles, which would be retained until about 1970 and run over the original LUT routes.

In 1941 and 1943 London Transport acquired 43 trolleybuses that had been ordered for South Africa but could not be shipped there because of the war.

They formed three different classes and needed special dispensation because they were eight feet wide, six inches more than the law then allowed.

Some later pre-war vehicles made use of modern monocoque construction techniques to produce chassisless bodies, where the mechanical and electrical parts, including the traction motors, are affixed to the bodywork and not to a separate chassis.

One experimental vehicle was proposed to be the forerunner of a small fleet that would use the Kingsway Tramway Subway, but proved in tests to be impractical.

A handful of pre-war vehicles were sold for further use in Penang (Malaysia), while most of the post-war ones were exported to Spain where they worked for various operators—some into the 1970s.

In 2012, it was proposed that a trolleybus based on the New Routemaster be introduced to address pollution concerns along Oxford Street.