London metropolitan area

The London Travel to Work Area in 2001 (dark blue), with the administrative boundary of Greater London shown.

The London Travel to Work Area, defined by the Office for National Statistics as the area for which "of the resident economically active population, at least 75% actually work in the area, and also, that of everyone working in the area, at least 75% actually live in the area."[5] has a population of 9,294,800 (2005 estimate).[6]

There are 17 local government districts that share a boundary with Greater London, in the East and South East regions. Most districts are entirely, or have sections, within the M25 motorway or are within 15–20 miles (24–32 km) of Charing Cross.

Adjacent districts often share characteristics of Outer London, such as forming part of the continuous urban sprawl, being served by the London Underground, being covered by the London telephone area code, (until 2000) forming part of the Metropolitan Police District and having a relatively high employed population working in London.

Larger Urban Zone is a definition created by Eurostat that measures the population and expanse of metropolitan areas across European countries. The population of London's Larger Urban Zone is 11.9 million (2004),[7] ranking it as the largest metropolitan area in the European Union until Brexit. The districts that are considered parts of this Larger Urban Zone are listed here:[8] no district in Bedfordshire, Hampshire, or Sussex is included. Several large conurbations fall just outside the zone: Reading, Luton, High Wycombe and significant parts of the Aldershot and Crawley Urban Areas.

The urban area of London (grey) extends beyond the London boundary. The M25 is also shown. The 020 telephone dialling code is shown in red.

The following table lists urban areas (also known as built-up areas) considered part of the London Commuter Belt with populations over 20,000.[9][10] The commuter belt contains all urban areas within an approximate 40 mile (64 km) radius of Charing Cross. Some of the outermost towns include Aylesbury, Reading, Aldershot and Maidstone.[11][12][13]

Some estate agents, including James Pendleton[15] and Savills[16] have defined a 'second commuter belt' further out of London and the home counties. The definition includes places up to approximately 55 miles (89 km) out of central London including Oxford, Hastings, Margate, Milton Keynes and Brighton.