Airports of London cannot be expanded due to the docks on either side. It is also the only airport serving London which does not operate at night. A light rail service from London City Airport DLR station, which adjoins the terminal building of London City Airport, links it to the financial district of the City of London at Bank and Monument stations, which offer interchanges with London Underground. Located in the London Borough of Hillingdon, Heathrow is by far the largest of London's airports and considered the main gateway into the United Kingdom for non-European visitors. Heathrow has four terminals and two parallel
History of the London Underground of London, Ken Livingstone, was sceptical about the practicality of the PPP plan, and brought in the American Bob Kiley as London's Transport Commissioner to repeat his success with the New York City Subway using public bond finance. Taking office in 2000 as London's first directly elected mayor, it was difficult for Livingstone to block the PPP process, which was entirely in the national Government's hands as it still owned London Underground, which was not transferred to local control until July 2003. Kiley was fired from the board of London Regional Transport (of which he had been chairman) in 2001