London Underground stations that are listed buildings London Underground stations that are listed buildings The London Underground is a metro system serving a large part of Greater London and parts of Buckinghamshire, Hertfordshire and Essex. Seventy-one of the 270 London Underground stations use buildings that are on the Statutory List of Buildings of Special Architectural or Historic Interest, and five have entrances in listed buildings. Buildings are given one of three grades: Grade I for buildings of exceptional interest, Grade II* for particularly important buildings of more than special interest and Grade II for buildings that are of special interest. The Metropolitan Railway's original seven stations were
London to amalgamate the city with its suburbs, causing "London" to be defined in a number of ways for different purposes. Forty per cent of Greater London is covered by the London post town, within which 'LONDON' forms part of postal addresses. The London telephone area code (020) covers a larger area, similar in size to Greater London, although some outer districts are excluded and some places just outside are included. The Greater London boundary has been aligned to the M25 motorway in places. Outward urban expansion is now prevented by the Metropolitan Green Belt, although the built-up area extends beyond