London is the starting point for a number of motorway routes. The M25 is an orbital motorway which enables vehicles to avoid travelling through central London and is one of the busiest motorways in Europe.
The railway was a precursor of parts of the London Underground's Northern line through its 1930s inclusion in the core of an ambitious expansion plan for that line. The EH&LR was to be transferred to the London Underground and electrified. Connections were to be constructed to the Northern line at Highgate and Edgware and to the Northern City Line, with an extension from Edgware to Bushey Heath. Works were stopped by the outbreak of the Second World War and only the work on the sections from Highgate to High Barnet and from Finchley Central to Mill Hill East were completed. The remainder of the line was closed in by British Railways the 1950s and is now disused.
Sir Leslie Patrick Abercrombie (6 June 1879 – 23 March 1957) was an English town planner. After training as an architect, he became Professor of Civic Design at the Liverpool University School of Architecture, and later Professor of Town Planning at University College London. He was closely involved in the founding of the Council for the Preservation of Rural England (CPRE). After its formation in December 1926, he served as its Honorary Secretary. He was knighted in 1945. In 1948, he became the first president of the newly formed International Union of Architects or UIA (Union Internationale des Architectes).
Abercrombie is best known for the post-Second World War replanning of London and other British and international cities. He created the County of London Plan (1943) and the Greater London Plan (1944) which are commonly referred to as the Abercrombie Plan. The two plans proposed widespread reconstruction and replanning of the city and the urban areas of the surrounding counties and road and rail infrastructure including the construction of a series of concentric ring roads and underground rail loops to connect main line stations below ground to replace surface routes.