Postal codes used in the United Kingdom, British Overseas Territories and Crown dependencies are known as postcodes. They are alphanumeric and were adopted nationally between 11 October 1959 and 1974, having been devised by the General Post Office . The system uses alphanumeric codes to designate geographic areas. A full postcode, also known as a "postcode unit", identifies a group of addresses or a major delivery point. It consists of an outward code and inward code. The outward code indicates the area and district, while the inward code specifies the sector and delivery point, typically encompassing about 15 addresses.
The London postal district is the area in England of 241 square miles (620 km2) to which mail addressed to the London post town is delivered. The General Post Office under the control of the Postmaster General directed Sir Rowland Hill to devise the area in 1856 and throughout its history it has been subject to reorganisation and division into increasingly smaller postal units, with the early loss of two compass points and a minor retraction in 1866. It was integrated by the Post Office into the national postcode system of the United Kingdom during the early 1970s and corresponds to the E, EC, N, NW, SE, SW, W and WC postcode areas. The postal district has also been known as the London postal area. The County of London was much smaller, at 117 square miles (300 km2), but Greater London is much larger at 607 square miles (1,570 km2).
The W postcode area, also known as the London W postcode area is a group of postcode districts covering part of central and part of West London, England. The area originates from the Western (W1) and Paddington (W2-14) districts of the London postal district. This area covers 35 postcode districts and around 18,554 live postcodes.
The RM postcode area, also known as the Romford postcode area, is a group of twenty postcode districts in south-east England, within nine post towns. These cover parts of eastern Greater London and south-west Essex. Inward mail for the area is sorted, along with mail for the E and IG postcode areas, at the Romford Mail Centre.
The IG postcode area, also known as the Ilford postcode area, is a group of eleven postcode districts in England, within six post towns. These cover parts of eastern Greater London and south-west Essex.
The EC postcode area, also known as the London EC postal area, is a group of postcode districts in central London, England. It includes almost all of the City of London and parts of the London boroughs of Islington, Camden, Hackney, Tower Hamlets and Westminster. The area covered is of very high density development. Deliveries for the EC postcode area are made from Mount Pleasant Mail Centre.
The WC postcode area, also known as the London WC postcode area, is a group of postcode districts in central London, England. The area covered is of high density development, and includes parts of the City of Westminster and the London Boroughs of Camden and Islington, plus a very small part of the City of London.
The KT postcode area, also known as the Kingston upon Thames postcode area, is a group of 24 postcode districts in England, within 19 post towns. These cover boroughs in south-west Greater London and several boroughs in north-east Surrey.
The SM postcode area, also known as the Sutton postcode area, is a group of seven postcode districts in England, within five post towns. These cover part of south-west London, as well as a small part of north Surrey.
The EN postcode area, also known as the Enfield postcode area, is a group of eleven postcode districts in England, within seven post towns. These cover parts of northern Greater London, southern Hertfordshire and western Essex.
The BR postcode area, also known as the Bromley postcode area, is a group of eight postcode districts in England, within seven post towns. These cover part of south-eastern Greater London, as well as a small part of north-west Kent.
The TW postcode area, also known as the Twickenham postcode area, is a group of twenty postcode districts in south-east England, within thirteen post towns. These cover parts of south-west London and north-west Surrey, plus a very small part of Berkshire.
The DA postcode area, also known as the Dartford postcode area, is a group of eighteen postcode districts in England, within eleven post towns. These cover parts of south-east London and north-west Kent.
The CM postcode area, also known as the Chelmsford postcode area, is a group of 25 postcode districts in England, within 16 post towns. These cover central Essex, plus a small part of east Hertfordshire and a very small part of the London Borough of Havering.
The UB postcode area, also known as the Southall postcode area, is a group of eleven postcode districts in England, within six post towns. These cover parts of western and north-western Greater London, plus a very small part of Buckinghamshire. The letters in the postcodes are the phonemic abbreviation of Uxbridge.
The HA postcode area, also known as the Harrow postcode area, is a group of ten postcode districts in England, within seven post towns. These cover part of northwest London, plus a very small part of south Hertfordshire.
The WD postcode area, also known as the Watford postcode area, is a group of eleven postcode districts in south-east England, within seven post towns. These cover south-west Hertfordshire, plus very small parts of Buckinghamshire and Greater London.
The SE postcode area covers a broad area of the south-east of the London, England post town from the Albert Embankment to West Heath and the nearest edges of Sidcup and Selhurst. It loosely corresponds to the boroughs of Southwark, Lewisham and Greenwich plus indicated parts of the boroughs of Croydon (north), Lambeth (east), Bexley (west) and Bromley (northwest).
The SW postcode area, also known as the London SW postcode area, is a group of 20 postcode districts within the London post town in England. The area comprises the South Western operational district and the Battersea operational district, and is the only area within the London post town to lie on both sides of the River Thames.
