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 ) .