Trolleybuses served the London Passenger Transport Area from 1931 until 1962. For much of its existence, the London system was the largest in the world. It peaked at 68 routes, with a maximum fleet of 1,811 trolleybuses.

The London Passenger Transport Board was the organisation responsible for local public transport in London and its environs from 1933 to 1948. In common with all London transport authorities from 1933 to 2000, the public name and brand was London Transport.