See also London population
LONDON usually refers to Greater London, an ever growing and evolving conurbation. Defining exactly what is meant by Greater London, and its exact boundaries is open to debate but administratively, Greater London is composed of the City of London
(see below) and the 32 London boroughs
Other definitions in common usage, but which designate different boundaries include the London postal districts, the areas covered by London's 020 phone number area code, the area inside the M25, the Metropolitan Police District and the London commuter belt. Hence there is no single definition of Greater London, and each one differs from the others considerably.
To confuse things further, the "City of London" is entirely different from Greater London. In fact Greater London contains within it two cities, the City of London and the City of Westminster.
The City of London, also known as "the City" or "the Square Mile" is a tiny area (approximately one square mile) right in the centre of Greater London which during the medieval period was the full extent of London, before the surrounding area became developed into today's Greater London.
Nowadays, despite its tiny area the City of London is Europe's largest central business district and financial district with a daily working population of over 300,000 people.
Greater London today is divided into two portions - Inner London and Outer London. The inner London boroughs are: Camden, Greenwich, Hackney, Hammersmith and Fulham, Islington, Kensington and Chelsea, Lambeth, Lewisham, Southwark, Tower Hamlets, Wandsworth and the City of Westminster.
Historically the inner zone comprised the fixed and permanent city, spreading in a continuous mass from Hampstead on the north to Norwood on the south, and from Bromley on the east to Hammersmith on the west. This area comprises, about 78,000 acres or 122 square miles.
The outer London boroughs are: Barking and Dagenham, Barnet, Bexley, Brent, Bromley, Croydon, Ealing, Enfield, Haringey, Harrow, Havering, Hillingdon, Hounslow, Kingston upon Thames, Merton, Newham, Redbridge, Richmond upon Thames, Sutton and Waltham Forest. Many of these outer London boroughs include large areas which are outside the Royal Mail's London postal district.
From one perspective London is not so much a city as a collection or gathering together of towns and villages. It has engulfed gradually many cities, towns, villages, and separate jurisdictions. Its present surface includes large portions of four ancient commonwealths, or kingdoms, those of the Middle Saxons (Middlesex), of the East Saxons (Essex), of the "South Rie" (Surrey) folk, and of Kent.
Greater London embraces not only the entire cities of London (the city of London) and Westminster, but the historic county of Middlesex (still used in postal addresses), all 32 inner and outer boroughs, numerous large like Woolwich and Wandsworth and the many once secluded and ancient villages such as Hanwell, Cheshunt, Harrow, Croydon, Finchley, Twickenham, Teddington, Chigwell, Sutton and Addington.
At the start of the twentieth century, Greater London was considered to bound the circle of the Metropolitan Police jurisdiction, which extended about fifteen miles from the centre of Charing Cross in every direction.
This embraced the whole of Middlesex and part of Surrey, together with most of the suburban districts of Essex and Kent, reaching from Dagenham in the east to Uxbridge in the west, and from Colney and Cheshunt in the north to Epsom and Warlingham in the south - an almost perfect circle, some twenty-eight miles in diameter.
One of the factors which influenced the development of Greater London during the rule of peers with their expansive estates was the law of proclamation. You can read more about that in the Influence of Proclamation on Greater London