Six preserved RT vintage London buses carried passengers through central London on Sunday in a special recreation of the old 77A route.
AEC Regent III RT buses were built between 1939 and the mid-1950s. The open-platform bus was the forerunner of the better-known Routemaster.
Sunday's service, with more than 25 passenger-carrying journeys in each direction, was a joint venture between the London Bus Company and Ensignbus.
Because of the Battle of Britain commemorations in Westminster on Sunday, buses were diverted via Westminster Bridge and Lambeth Palace Road for part of the day.
Two RT buses were rebuilt into a triple-decker vehicle known as the Knight Bus for Harry Potter and the Prisoner of Azkaban.