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. A full postcode is known as a "postcode unit" and designates an area with several addresses or a single major delivery point.
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 E (Eastern) postcode area, also known as the London E postcode area, is the part of the London post town covering much of east London, England. It borders the N postcode area to the west, both north of the tidal Thames. Since closure of the East London mail centre, its mail is sorted at Romford Mail Centre together with IG and RM postcode areas.
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 CR postcode area, also known as the Croydon postcode area, is a group of eight postcode districts in England, within ten post towns. These cover parts of southern Greater London and north-east Surrey.
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 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 WD postcode area, also known as the Watford postcode area, is a group of eleven postcode districts in Greater London and Hertfordshire, within seven post towns. These cover south-west Hertfordshire, plus very small parts of Buckinghamshire and the London Borough of Hillingdon.
The NW postcode area, also known as the London NW postcode area, is a group of 13 postcode districts covering around 13,895 live postcodes within part of northwest London, England. It is the successor of the NW sector, originally created as part of the London postal district in 1856.
The SG postcode area, also known as the Stevenage postcode area, is a group of nineteen postcode districts in England, within fifteen post towns. These cover north Hertfordshire and east Bedfordshire, plus a small part of south-west Cambridgeshire and a very small part of Essex.
The NE postcode area, also known as the Newcastle upon Tyne postcode area, is a group of 61 postcode districts in north-east England covering 34 post towns. These cover most of Tyne and Wear and Northumberland, plus a very small part of northern County Durham. The NE postcode area is one of six with a population above 1 million.
The N (Northern) postcode area, also known as the London N postcode area, is the part of the London post town covering part of North London, England. It is a group of 25 postcode districts which covers around 17,429 live postcodes.
The L postcode area, also known as the Liverpool postcode area, is a group of postcode districts in North West England. Together they cover central and southern Merseyside, southern West Lancashire, and a small part of north-west Cheshire. Its four post towns are Bootle, Liverpool, Ormskirk, and Prescot.
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.
