Original: London Transport In 1933 the Combine, the Metropolitan and all the municipal and independent bus and tram undertakings were merged into the London Passenger Transport Board (LPTB), a self-supporting and unsubsidised public corporation which came into being on 1 July 1933.
Simplified: In the 1930s and 1940s In 1933 a company was formed of all the bus, tram and underground companies, called London Passenger Transport Board (LPTB).