Founded in 1933 by an act of Parliament under Transport Minister Herbert Stanley Morrison, The London Passenger Transport Board generally known London Transport was "A public authority appointed under act of Parliament, charged with responsibility for providing an adequate and properly co-ordinated system of passenger transport (Buses including Green Line Coaches, Trams & Underground) within the LONDON PASSENGER TRANSPORT AREA, (An area within a Radius of 30 miles from Charing Cross)", Extending from Baldock in the North, to Brentwood in the East, Horsham in the South and High Wycombe in the West.

It was nationalised in 1948 becoming the London Transport Executive.

Most of its functions were transferred to Transport for London in 2000 when the Mayor of London and the London Assembly were established.

The London Underground was transferred to TfL in 2003 when the public-private partnership was completed.