London Underground ticketing destinations and most interchange stations are in zone 1, meaning that most journeys over similar distances will cost the same. A few stations in the north east of the network, on the Central line, outside Greater London (in the Epping Forest district) are in zones 4, 5 and 6. In the north west of the network, on the Metropolitan line, zones 7, 8 and 9 (formerly A - D) cover stations outside Greater London including Amersham and Chesham in the Chiltern district of Buckinghamshire. Unlike the lower numbered zones, these ancillary areas do not encircle the capital. Some stations are
M25 motorway of London, part of the London Orbital. The combined motorway was given the designation M25 which had originally been intended for the southern and western part of Ringway 4 and the M16 designation was dropped. The section of Ringway 3 west of South Mimms anti-clockwise around London to Swanley in Kent was cancelled. The stages were not constructed contiguously but in small sections. As the orbital road developed the sections were linked. Each section was presented to planning authorities in its own right and was individually justified, with almost 40 public inquiries relating to sections of the route. Maps at