M25 motorway "Inside the M25" and "outside/beyond the M25" are colloquial, looser alternatives to "Greater London" sometimes used in haulage. The Communications Act 2003 explicitly uses the M25 as the boundary in requiring a proportion of television programmes to be made outside the London area. Two motorway service areas are on the M25, and two others are directly accessible from it. Those on the M25 are Clacket Lane between junctions 5 and 6 (in the south-east) and Cobham between junctions 9 and 10 (in the south-west). Those directly accessible from it are South Mimms off junction 23 (to the north of London)
Greater London boundary with Kent, at 245 metres (804 ft). Central government has implemented small boundary changes. The greatest were the 1969 transfers of Farleigh to Surrey and Knockholt to Kent. Others have included exchange of two Thames islands with Surrey and adjustments during the 1990s to parts of the boundaries of three boroughs near the M25. The only part of Greater London outside the motorway is North Ockendon, the furthest land unit from its centre. The majority of Greater London forms the London low emission zone. The London postal district does not cover all of Greater London. The Mayor of London