After the formation of the London Passenger Transport Board in 1933, the MR was amalgamated with the other Underground railways and the line was renamed the Northern City Line. In 1934 it was re-branded as part of the Edgware–Morden line (which was renamed the Northern line in 1937), and in 1939 operations were transferred from the Metropolitan to the Northern. As part of London Transport's New Works Programme, the Northern Heights plan was to connect the Northern City Line at Finsbury Park to existing main-line suburban branches running to Alexandra Palace, High Barnet and Edgware, which would be taken over by London Transport and electrified. The Highgate branch of the Edgware–Morden line would connect to this network north of Highgate. Only parts of this plan were completed: when the Second World War started, the Highgate link and electrification of the Barnet branch were well under way and ultimately completed, but the Northern City connection to Highgate was first postponed and finally cancelled after the war.