Postcodes In The United Kingdom
   HOME

TheInfoList



OR:

Postal code A postal code (also known locally in various English-speaking countries throughout the world as a postcode, post code, PIN or ZIP Code) is a series of letters or digits or both, sometimes including spaces or punctuation, included in a postal a ...
s used in the
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
,
British Overseas Territories The British Overseas Territories (BOTs), also known as the United Kingdom Overseas Territories (UKOTs), are fourteen dependent territory, territories with a constitutional and historical link with the United Kingdom. They are the last remna ...
and Crown dependencies are known as postcodes (originally, postal codes). They are
alphanumeric Alphanumericals or alphanumeric characters are a combination of alphabetical and numerical characters. More specifically, they are the collection of Latin letters and Arabic digits. An alphanumeric code is an identifier made of alphanumeric c ...
and were adopted nationally between 11 October 1959 and 1974, having been devised by the General Post Office ( Royal Mail). A full postcode is known as a "postcode unit" and designates an area with several addresses or a single major delivery point. The structure of a postcode is two alphanumeric codes that show, first, the Post Town and, second, a small group of addresses in that post town. The first alphanumeric code (the Outward code or Outcode) has between two and four characters and the second (the Inward Code or Incode) always has three characters. The Outcode indicates the postcode area and postcode district. It consists of one or two letters, followed by one digit, two digits, or one digit and one letter. This is followed by a space and then the Incode which indicates the postcode sector and delivery point (usually a group of around 15 addresses). The incode always has 3 characters, starting with a number (denoting a sector within the district), and ending with two letters (denoting delivery points which are allocated to streets, sides of a street or individual properties). Postcode areas are usually, but not always, named after a major town or city — such as B for Birmingham. A small number are geographic in nature — such as HS for the Outer Hebrides and FY for Fylde (the region around Blackpool). Each postcode area contains a number of post towns which are not themselves alphabetically denoted; however each will generally constitute one or more postcode districts. Example: a sizeable part of southern England is covered by the GU postcode area, named after the town of Guildford. Guildford itself consists of postal districts GU1 and GU2. Nearby Woking, a major commuter town— away—is a post town within the postal district GU22. The central part of the town/city the postcode area is named after will have the number 1 e.g. B1 (Birmingham), LS1 (Leeds), M1 (Manchester). However, other post towns within the area are then either treated alphabetically—particularly in London—e.g. Chingford on the north-eastern edge of London being E4, whereas adjacent Walthamstow to the south being E17–or geographically— e.g. the Outer Hebrides area HS numbering the districts north to south. As a general rule, large post towns are numbered from the centre outward such that outlying parts have higher numbered districts. However, the disparate post towns within a postal area can be numbered based on various criteria. The town the postal area is named after excepted, this always being 1. In particular, the centrality of a postcode district within a postcode area cannot be reliably inferred from the postcode alone. For instance, SE1 covers a large part of Central London south of the Thames whereas SE2 covers Abbey Wood at the far end of the Elizabeth Line. See postcode area. Postcodes have been adopted for a wide range of purposes in addition to aiding the sorting of mail: for calculating insurance premiums, designating destinations in
route planning software A journey planner, trip planner, or route planner is a specialized search engine used to find an optimal means of travelling between two or more given locations, sometimes using more than one transport mode. Searches may be optimized on differen ...
and as the lowest level of aggregation in
census A census is the procedure of systematically acquiring, recording and calculating information about the members of a given population. This term is used mostly in connection with national population and housing censuses; other common censuses incl ...
enumeration. The boundaries of each postcode unit and within these the full address data of currently about 29 million addresses (delivery points) are stored, maintained and periodically updated in the
Postcode Address File The Postcode Address File (PAF) is a database that contains all known "delivery points" and postcodes in the United Kingdom. The PAF is a collection of over 29 million Royal Mail postal addresses and 1.8 million postcodes. It is available i ...
database. The initial system of named postal districts, developed in London and other large cities from 1857, evolved towards the present form: in 1917 London was split into broad numbered subdivisions, and this extended to the other cities in 1934. Theoretically, deliveries can reach their destination using the house number (or name if the house has no number) and postcode alone; however, this is against Royal Mail guidelines, which request the use of a full address.


History


Earlier postal districts


London

The London post town covers 40% of Greater London. On inception (in 1857/8), it was divided into ten postal districts: EC (East Central), WC (West Central), N, NE, E, SE, S, SW, W, and NW. The S and NE sectors were later abolished. In 1917, as a wartime measure to improve efficiency, each postal district was subdivided into sub-districts each identified by a number; the area served directly by the district head office was allocated the number 1; the other numbers were allocated alphabetically by delivery office, e.g. N2 East Finchley delivery office, N3 Finchley delivery office, N4 Finsbury Park delivery office etc. Since then these sub-districts have changed little. Some older road signs in Hackney still show the North East (NE) sector/district.


Other large cities and towns

Following the successful introduction of postal districts in London, the system was extended to other large towns and cities. Liverpool was divided into Eastern, Northern, Southern and Western districts in 1864/65, and Manchester and Salford into eight numbered districts in 1867/68. In 1917,
Dublin Dublin (; , or ) is the capital and largest city of Ireland. On a bay at the mouth of the River Liffey, it is in the province of Leinster, bordered on the south by the Dublin Mountains, a part of the Wicklow Mountains range. At the 2016 c ...
—then still part of the United Kingdom—was divided into numbered postal districts. These continue in use in a modified form by An Post, the postal service of the
Republic of Ireland Ireland ( ga, Éire ), also known as the Republic of Ireland (), is a country in north-western Europe consisting of 26 of the 32 counties of the island of Ireland. The capital and largest city is Dublin, on the eastern side of the island. A ...
. In 1923, Glasgow was divided in a similar way to London, with numbered districts preceded by a letter denoting the compass point (C, W, NW, N, E, S, SW, SE). In January 1932 the Postmaster General approved the designation of some predominantly urban areas into numbered districts. In November 1934 the Post Office announced the introduction of numbered districts (short postal codes) in "every provincial town in the United Kingdom large enough to justify it". Pamphlets were issued to each householder and business in ten areas notifying them of the number of the district in which their premises lay. The pamphlets included a map of the districts, and copies were made available at local head post offices. The public were "particularly invited" to include the district number in the address at the head of letters. A publicity campaign in the following year encouraged the use of the district numbers. The slogan for the campaign was "For speed and certainty always use a postal district number on your letters and notepaper". A poster was fixed to every pillar box in the affected areas bearing the number of the district and appealing for the public's co-operation. Every post office in the numbered district was also to display this information. Printers of Christmas cards and stationery were requested to always include district numbers in addresses, and
election agent An election agent in elections in the United Kingdom, as well as some other similar political systems such as elections in India, is the person legally responsible for the conduct of a candidate's political campaign and to whom election material is ...
s for candidates in the upcoming general election were asked to ensure they correctly addressed the 100 million items of mail they were expected to post. Businesses were issued with a free booklet containing maps and listings of the correct district number for every street in the ten areas. The ten areas were: *
Birmingham Birmingham ( ) is a city and metropolitan borough in the metropolitan county of West Midlands in England. It is the second-largest city in the United Kingdom with a population of 1.145 million in the city proper, 2.92 million in the West ...
* Brighton/
Hove Hove is a seaside resort and one of the two main parts of the city of Brighton and Hove, along with Brighton in East Sussex, England. Originally a "small but ancient fishing village" surrounded by open farmland, it grew rapidly in the 19th c ...
*
Bristol Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...
*
Edinburgh Edinburgh ( ; gd, Dùn Èideann ) is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. Historically part of the county of Midlothian (interchangeably Edinburghshire before 1921), it is located in Lothian ...
*
Glasgow Glasgow ( ; sco, Glesca or ; gd, Glaschu ) is the most populous city in Scotland and the fourth-most populous city in the United Kingdom, as well as being the 27th largest city by population in Europe. In 2020, it had an estimated popul ...
*
Leeds Leeds () is a city and the administrative centre of the City of Leeds district in West Yorkshire, England. It is built around the River Aire and is in the eastern foothills of the Pennines. It is also the third-largest settlement (by populati ...
/
Bradford Bradford is a city and the administrative centre of the City of Bradford district in West Yorkshire, England. The city is in the Pennines' eastern foothills on the banks of the Bradford Beck. Bradford had a population of 349,561 at the 2011 ...
*
Liverpool Liverpool is a city and metropolitan borough in Merseyside, England. With a population of in 2019, it is the 10th largest English district by population and its metropolitan area is the fifth largest in the United Kingdom, with a popul ...
*
Manchester Manchester () is a city in Greater Manchester, England. It had a population of 552,000 in 2021. It is bordered by the Cheshire Plain to the south, the Pennines to the north and east, and the neighbouring city of Salford to the west. The t ...
/
Salford Salford () is a city and the largest settlement in the City of Salford metropolitan borough in Greater Manchester, England. In 2011, Salford had a population of 103,886. It is also the second and only other city in the metropolitan county afte ...
*
Newcastle upon Tyne Newcastle upon Tyne ( RP: , ), or simply Newcastle, is a city and metropolitan borough in Tyne and Wear, England. The city is located on the River Tyne's northern bank and forms the largest part of the Tyneside built-up area. Newcastle is ...
*
Sheffield Sheffield is a city status in the United Kingdom, city in South Yorkshire, England, whose name derives from the River Sheaf which runs through it. The city serves as the administrative centre of the City of Sheffield. It is Historic counties o ...
For example,
Toxteth Toxteth is an inner-city area of Liverpool in the historic county of Lancashire and the ceremonial county of Merseyside. Toxteth is located to the south of Liverpool city centre, bordered by Aigburth, Canning, Dingle, and Edge Hill. The area ...
was ''Liverpool 8''. A single numbering sequence was shared by Manchester and Salford: letters would be addressed to Manchester 1 or Salford 7 (lowest digits, respectively). Some Birmingham codes were sub-divided with a letter, such as ''Great Barr, Birmingham 22'' or ''Birmingham 22a'', as can still be seen on many older street-name signs.


Modern postcode system

The Post Office experimented with electromechanical sorting machines in the late 1950s. These devices presented an envelope to an operator, who would press a button indicating which bin to sort the letter into. Postcodes were suggested to increase the efficiency of this process by removing the need for the sorter to remember the correct sorting for as many places.''New Scientist'', 21 July 2007, p16 In January 1959 the Post Office analysed the results of a survey on public attitudes towards the use of postal codes, choosing a town in which to experiment with codes. The envisaged format was a six-character alphanumeric code with three letters designating the geographical area and three numbers to identify the individual address."Postal codes to speed up mail", ''The Times'', 15 January 1959 On 28 July
Ernest Marples Alfred Ernest Marples, Baron Marples, (9 December 1907 – 6 July 1978) was a British Conservative politician who served as Postmaster General (1957–1959) and Minister of Transport (1959–1964). As Postmaster General, he oversaw the introdu ...
, the
Postmaster General A Postmaster General, in Anglosphere countries, is the chief executive officer of the postal service of that country, a ministerial office responsible for overseeing all other postmasters. The practice of having a government official responsib ...
, announced that
Norwich Norwich () is a cathedral city and district of Norfolk, England, of which it is the county town. Norwich is by the River Wensum, about north-east of London, north of Ipswich and east of Peterborough. As the seat of the See of Norwich, with ...
had been selected, and that each of the 150,000 private and business addresses would receive a code by October. Norwich had been selected as it already had eight automatic mail sorting machines in use."Norwich to use postal codes – Experimenting in automation", ''The Times'', 29 July 1959 The original Norwich format consisted of "NOR," followed by a space, then a two-digit number (which, unlike the current format, could include a leading zero), and finally a single letter (instead of the two final letters in the current format).Examples of Norwich NOR postcodes in the old format: "NOR 03Z", "NOR 66F", "NOR 83B", "NOR 05S". In October 1965,
Tony Benn Anthony Neil Wedgwood Benn (3 April 1925 – 14 March 2014), known between 1960 and 1963 as Viscount Stansgate, was a British politician, writer and diarist who served as a Cabinet minister in the 1960s and 1970s. A member of the Labour Party, ...
as Postmaster General announced that postal coding was to be extended to the rest of the country in the next few years."G.P.O. robot postman sorts 20,000 letters an hour", ''The Times'', 5 October 1965 On 1 May 1967 postcodes were introduced in
Croydon Croydon is a large town in south London, England, south of Charing Cross. Part of the London Borough of Croydon, a local government district of Greater London. It is one of the largest commercial districts in Greater London, with an extensi ...
. The many postcodes for central Croydon began with "CRO", while those of the surrounding
post town A post town is a required part of all postal addresses in the United Kingdom and Ireland, and a basic unit of the postal delivery system.Royal Mail, ''Address Management Guide'', (2004) Including the correct post town in the address increases ...
s with CR2, CR3 and CR4. The uniform system of a set of three final characters after the space (such as 0AA, known as the inward code) was adopted. This was to be the beginning of a ten-year plan, costing an estimated £24 million. Within two years it was expected that full coding would be used in
Aberdeen Aberdeen (; sco, Aiberdeen ; gd, Obar Dheathain ; la, Aberdonia) is a city in North East Scotland, and is the third most populous city in the country. Aberdeen is one of Scotland's 32 local government council areas (as Aberdeen City), and ...
,
Belfast Belfast ( , ; from ga, Béal Feirste , meaning 'mouth of the sand-bank ford') is the capital and largest city of Northern Ireland, standing on the banks of the River Lagan on the east coast. It is the 12th-largest city in the United Kingdo ...
, Brighton,
Bristol Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...
,
Bromley Bromley is a large town in Greater London, England, within the London Borough of Bromley. It is south-east of Charing Cross, and had an estimated population of 87,889 as of 2011. Originally part of Kent, Bromley became a market town, c ...
,
Cardiff Cardiff (; cy, Caerdydd ) is the capital and largest city of Wales. It forms a principal area, officially known as the City and County of Cardiff ( cy, Dinas a Sir Caerdydd, links=no), and the city is the eleventh-largest in the United Kingd ...
,
Coventry Coventry ( or ) is a City status in the United Kingdom, city in the West Midlands (county), West Midlands, England. It is on the River Sherbourne. Coventry has been a large settlement for centuries, although it was not founded and given its ...
,
Manchester Manchester () is a city in Greater Manchester, England. It had a population of 552,000 in 2021. It is bordered by the Cheshire Plain to the south, the Pennines to the north and east, and the neighbouring city of Salford to the west. The t ...
,
Newcastle upon Tyne Newcastle upon Tyne ( RP: , ), or simply Newcastle, is a city and metropolitan borough in Tyne and Wear, England. The city is located on the River Tyne's northern bank and forms the largest part of the Tyneside built-up area. Newcastle is ...
, Newport,
Reading Reading is the process of taking in the sense or meaning of letters, symbols, etc., especially by sight or touch. For educators and researchers, reading is a multifaceted process involving such areas as word recognition, orthography (spelling ...
,
Sheffield Sheffield is a city status in the United Kingdom, city in South Yorkshire, England, whose name derives from the River Sheaf which runs through it. The city serves as the administrative centre of the City of Sheffield. It is Historic counties o ...
,
Southampton Southampton () is a port city in the ceremonial county of Hampshire in southern England. It is located approximately south-west of London and west of Portsmouth. The city forms part of the South Hampshire built-up area, which also covers Po ...
and the Western district of London."Someone, Somewhere in postal code", ''The Times'', 12 October 1966 By 1967, codes had been introduced to Aberdeen, Southampton, Brighton and
Derby Derby ( ) is a city and unitary authority area in Derbyshire, England. It lies on the banks of the River Derwent in the south of Derbyshire, which is in the East Midlands Region. It was traditionally the county town of Derbyshire. Derby g ...
."Post Office plans faster service", ''The Times'', 4 July 1967 In 1970, codes were introduced to the London Western and North Western postal districts."London in brief", ''The Times'', 15 September 1970 In December 1970, much Christmas mail was postmarked with the message "Remember to use the Postal Code" although codes were used to sort mail in only a handful of
sorting office A sorting office or processing and distribution center (P&DC; name used by the United States Postal Service (USPS)) is any location where postal operators bring mail after collection for sorting into batches for delivery to the addressee, which ...
s."Inside the Post Office", ''The Times'', 18 January 1971 During 1971, occupants of addresses began to receive notification of their postcode. Asked in the House of Commons about the completion of the coding exercise, the
Minister of State Minister of State is a title borne by politicians in certain countries governed under a parliamentary system. In some countries a Minister of State is a Junior Minister of government, who is assigned to assist a specific Cabinet Minister. In ...
for Posts and Telecommunications (whose role superseded that of Postmaster General in 1969), Sir John Eden, stated that it was expected to be completed during 1972."Postal code programme", ''The Times'', 20 April 1972 The scheme was finalised in 1974 when Norwich was completely re-coded but the scheme tested in Croydon was sufficiently close to the final design for it to be retained, with CRO standardised as CR0 (district zero) thus removing the need to create a CR1 district.Information Sheet: Postcodes
, British Postal Museum and Archive
A quirk remained: the central Newport (Gwent) area was allocated NPT at a similar time to Croydon becoming CRO, and surrounding areas were (as today) allocated NP1–NP8. NPT lasted until the end of 1984 when it was recoded NP9.
Girobank National Girobank was a British public sector financial institution run by the General Post Office that opened for business in October 1968. It started life as ''National Giro''  then ''National Girobank'' and finally ''Girobank plc'' be ...
's GIR 0AA was the last domestic postcode with a fully alphabetical outward code. That code no longer exists in the Royal Mail's PAF system, but was taken over by the bank's current owners,
Santander UK Santander UK plc (, ) is a British bank, wholly owned by the Spanish Santander Group. Santander UK plc manages its affairs autonomously, with its own local management team, responsible solely for its performance. Santander UK is one of the l ...
.


Adaptation of earlier systems into national system

When the national postcode system was introduced, many existing postal districts were incorporated into it, so that postcodes in Toxteth (Liverpool 8) start with L8. The districts in both Manchester and Salford gained M postcodes, so Salford 7 became M7 and so on (and similarly in Brighton and Hove, both using the prefix BN). The old coding lives on in a small number of street signs with (for example) "Salford 7" at the bottom. In other cases, the district numbers were replaced with unrelated numbers. In Glasgow many of its G-prefixed numbers are not used as C1 became G1, W1 became G11, N1 became G21, E1 became G31, S1 became G41, SW1 became G51, and so on. In London (as postally defined), 1917-created postal districts are mapped unchanged to those of today but its much enlarged administrative area, Greater London, was created in April 1965. From that month the remaining 60% of Greater London's area has postcodes referring to 13 other post towns. Additionally, there were too few postcodes to adequately cover districts in central London (particularly in the WC and EC areas), so these were subdivided with a letter suffix rather than being split into new numbered districts so as to retain the familiar codes.


GB postcodes available as OpenData

Prior to 1 April 2010, the Royal Mail licensed use of the postcode database for a charge of about £4,000 per year. Following a campaign and a government consultation in 2009, the Ordnance Survey released Code-Point Open, detailing each current postcode in Great Britain together with a geo-code for re-use free of charge under an attribution-only licence (
Open Government Licence The Open Government Licence is a copyright licence for Crown copyright works published by the UK government. Other UK public sector bodies may apply it to their publications. It was developed and is maintained by The National Archives. It is co ...
as part of OS OpenData).


Postcodes linked to a variety of UK geographies

The
Office for National Statistics The Office for National Statistics (ONS; cy, Swyddfa Ystadegau Gwladol) is the executive office of the UK Statistics Authority, a non-ministerial department which reports directly to the UK Parliament. Overview The ONS is responsible for t ...
(ONS Geography) maintains and publishes a series of freely available, downloadable postcode products that link all current and terminated UK postcodes to a range of administrative, health, statistical and other geographies using the Code-Point Open grid reference.


Formatting


Overview

The postcodes are alphanumeric, and are variable in length: ranging from six to eight characters (including a space). Each postcode is divided into two parts separated by a single space: the ''outward code'' and the ''inward code'' respectively. The ''outward code'' includes the ''postcode area'' and the ''postcode district'', respectively. The ''inward code'' includes the ''postcode sector'' and the ''postcode unit'' respectively. Examples of postcodes are "SW1W 0NY", "PO16 7GZ", "GU16 7HF", and "L1 8JQ".


Outward code

The outward code is the part of the postcode before the single space in the middle. It is between two and four characters long. Examples of outward codes are "L1", "W1A", "RH1", "RH10" or "SE1P". A few outward codes are non-geographic, not divulging where mail is to be sent.


Postcode area

The postcode area is part of the outward code. The postcode area is either one or two characters long and is alphabetical. Examples of postcode areas are "L" for
Liverpool Liverpool is a city and metropolitan borough in Merseyside, England. With a population of in 2019, it is the 10th largest English district by population and its metropolitan area is the fifth largest in the United Kingdom, with a popul ...
, "RH" for Redhill and "EH" for
Edinburgh Edinburgh ( ; gd, Dùn Èideann ) is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. Historically part of the county of Midlothian (interchangeably Edinburghshire before 1921), it is located in Lothian ...
. A postal area may cover a wide area, for example "RH" also covers parts of north Sussex and "BT" (
Belfast Belfast ( , ; from ga, Béal Feirste , meaning 'mouth of the sand-bank ford') is the capital and largest city of Northern Ireland, standing on the banks of the River Lagan on the east coast. It is the 12th-largest city in the United Kingdo ...
) covers the whole of
Northern Ireland Northern Ireland ( ga, Tuaisceart Éireann ; sco, label= Ulster-Scots, Norlin Airlann) is a part of the United Kingdom, situated in the north-east of the island of Ireland, that is variously described as a country, province or region. Nort ...
.


Postcode district

The postcode district is one digit, two digits or a digit followed by a letter.


Inward code

The inward code is the part of the postcode after the single space in the middle. It is three characters long. The inward code assists in the delivery of post within a postal district. Examples of inward codes are "0NY", "7GZ", "7HF", or "8JQ".


Postcode sector

The postcode sector is made up of a single digit (the first character of the inward code).


Postcode unit

The postcode unit is two characters added to the end of the postcode sector. A postcode unit generally represents a street, part of a street, a single address, a group of properties, a single property, a sub-section of the property, an individual organisation or (for instance
Driver and Vehicle Licensing Agency The Driver and Vehicle Licensing Agency (DVLA; cy, Asiantaeth Trwyddedu Gyrwyr a Cherbydau) is the organisation of the UK government responsible for maintaining a database of drivers in Great Britain and a database of vehicles for the entire ...
) a subsection of the organisation. The level of discrimination is often based on the amount of mail received by the premises or business.


Validation

The format is as follows, where A signifies a letter and 9 a digit: Notes: * As all formats end with 9AA, the first part of a postcode can easily be extracted by ignoring the last three characters. * Areas with only single-digit districts: BR, FY, HA, HD, HG, HR, HS, HX, JE, LD, SM, SR, WC, WN, ZE (although WC is always subdivided by a further letter, e.g. WC1A) * Areas with only double-digit districts: AB, LL, SO * Areas with a district '0' (zero): BL, BS, CM, CR, FY, HA, PR, SL, SS (BS is the only area to have both a district 0 and a district 10) * The following central London single-digit districts have been further divided by inserting a letter after the digit and before the space: EC1–EC4 (but not EC50), SW1, W1, WC1, WC2 and parts of E1 (E1W), N1 (N1C and N1P), NW1 (NW1W) and SE1 (SE1P). * The letters ''Q'', ''V'' and ''X'' are not used in the first position. * The letters ''I'', ''J'' and ''Z'' are not used in the second position. * The only letters to appear in the third position are ''A'', ''B, C, D, E, F, G, H, J, K, P, S, T, U'' and ''W'' when the structure starts with A9A. * The only letters to appear in the fourth position are ''A, B, E, H, M, N, P, R, V, W, X'' and ''Y'' when the structure starts with AA9A. * The final two letters do not use ''C, I, K, M, O'' or ''V'', so as not to resemble digits or each other when hand-written. * Postcode sectors are one of ten digits: 0 to 9, with 0 only used once 9 has been used in a post town, save for Croydon and Newport (see above). A postcode can be validated against a table of all 1.7 million postcodes i
Code-Point Open
The full delivery address including postcode can be validated against the Royal Mail
Postcode Address File The Postcode Address File (PAF) is a database that contains all known "delivery points" and postcodes in the United Kingdom. The PAF is a collection of over 29 million Royal Mail postal addresses and 1.8 million postcodes. It is available i ...
(PAF), which lists 29 million valid delivery addresses,Postcodes to celebrate 50th year
BBC News BBC News is an operational business division of the British Broadcasting Corporation (BBC) responsible for the gathering and broadcasting of news and current affairs in the UK and around the world. The department is the world's largest broadca ...
, 30 December 2008
constituting most (but not all) addresses in the UK. The following
regular expression A regular expression (shortened as regex or regexp; sometimes referred to as rational expression) is a sequence of characters that specifies a search pattern in text. Usually such patterns are used by string-searching algorithms for "find" ...
can be used for the purpose of validation: ^ -Z0-9] -Z0-9 ? -9A-Z]$ The following regular expression can be used for the purpose of validation and includes postcode formats from Postcodes in the United Kingdom#Special cases, Special Cases: ^(( -Z0-9] -Z0-9, ASCN, STHL, TDCU, BBND, FSQQ, PCRN, TKCA) ? -9A-Z], BFPO ? -9(KY -9MSR, VG, AI) - -9 -Z? -9GE ?CX, GIR ?0A, SAN ?TA1)$


Post towns

All or part of one or more postcode districts are grouped into
post town A post town is a required part of all postal addresses in the United Kingdom and Ireland, and a basic unit of the postal delivery system.Royal Mail, ''Address Management Guide'', (2004) Including the correct post town in the address increases ...
s. Larger post towns may use more than one postcode district, for example Crawley uses RH10 and RH11. In a minority of cases, a single number can cover two post towns—for example, the WN8 district includes Wigan and Skelmersdale post towns.


Special cases


Crown dependencies

The
Channel Islands The Channel Islands ( nrf, Îles d'la Manche; french: îles Anglo-Normandes or ''îles de la Manche'') are an archipelago in the English Channel, off the French coast of Normandy. They include two Crown Dependencies: the Bailiwick of Jersey, ...
and the
Isle of Man ) , anthem = "O Land of Our Birth" , image = Isle of Man by Sentinel-2.jpg , image_map = Europe-Isle_of_Man.svg , mapsize = , map_alt = Location of the Isle of Man in Europe , map_caption = Location of the Isle of Man (green) in Europe ...
established their own postal administrations separate from the UK in 1969. Despite this, they adopted the UK-format postcodes in 1993–94: Guernsey using GY, the Isle of Man using IM, and
Jersey Jersey ( , ; nrf, Jèrri, label= Jèrriais ), officially the Bailiwick of Jersey (french: Bailliage de Jersey, links=no; Jèrriais: ), is an island country and self-governing Crown Dependency near the coast of north-west France. It is the l ...
using JE.Written_Answer_[87341
/nowiki>.html" ;"title="7341">Written Answer [87341
/nowiki>">7341">Written Answer [87341
/nowiki> House of Commons Hansard, 17 December 2002, column 739W.
The independent jurisdiction of Sark was assigned a unique postcode prefix GY10 in 2011 to differentiate it from Alderney. The CEO of Guernsey Post, Boley Smillie, said "this has been a long time coming" and "... Sark should have had its own identity back then hen postcodes were adopted in 1993.


British Overseas Territories

Some of the
British Overseas Territories The British Overseas Territories (BOTs), also known as the United Kingdom Overseas Territories (UKOTs), are fourteen dependent territory, territories with a constitutional and historical link with the United Kingdom. They are the last remna ...
have postcodes that follow the format of the UK postcode system: These were introduced because mail was often sent to the wrong place, e.g., for St Helena to St Helens,
Isle of Wight The Isle of Wight ( ) is a county in the English Channel, off the coast of Hampshire, from which it is separated by the Solent. It is the largest and second-most populous island of England. Referred to as 'The Island' by residents, the Isle of ...
. and Ascension Island to
Asunción Asunción (, , , Guarani: Paraguay) is the capital and the largest city of Paraguay. The city stands on the eastern bank of the Paraguay River, almost at the confluence of this river with the Pilcomayo River. The Paraguay River and the Bay of ...
,
Paraguay Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ...
, and many online companies would not accept addresses without a postcode. Mail from the UK continues to be treated as international, not inland, and sufficient postage must be used.
Bermuda ) , anthem = "God Save the King" , song_type = National song , song = "Hail to Bermuda" , image_map = , map_caption = , image_map2 = , mapsize2 = , map_caption2 = , subdivision_type = Sovereign state , subdivision_name = , es ...
, the UK's most populous remaining overseas territory, has developed its own postcode system, with unique postcodes for street and PO Box addresses, as have the Cayman Islands, Montserrat and the
British Virgin Islands ) , anthem = "God Save the King" , song_type = Territorial song , song = " Oh, Beautiful Virgin Islands" , image_map = File:British Virgin Islands on the globe (Americas centered).svg , map_caption = , mapsize = 290px , image_map2 = Bri ...
. Montserrat recently introduced postal codes, and a system has been under consideration in
Gibraltar ) , anthem = " God Save the King" , song = " Gibraltar Anthem" , image_map = Gibraltar location in Europe.svg , map_alt = Location of Gibraltar in Europe , map_caption = United Kingdom shown in pale green , mapsize = , image_map2 = Gib ...
with the code GX11 1AA being introduced as the generic postcode for the territory in the interim. The British Sovereign Base Areas of
Akrotiri and Dhekelia Akrotiri and Dhekelia, officially the Sovereign Base Areas of Akrotiri and Dhekelia (SBA),, ''Periochés Kyríarchon Váseon Akrotiríou ke Dekélias''; tr, Ağrotur ve Dikelya İngiliz Egemen Üs Bölgeleri is a British Overseas Territory o ...
in Cyprus use Cypriot postal codes for civilian use. The British military use BFPO addresses. The separate postal code systems for those territories are shown below:


British Forces Post Office (BFPO)

The
British Forces Post Office The British Forces Post Office (BFPO) provides a postal service to HM Forces, separate from that provided by Royal Mail in the United Kingdom. BFPO addresses are used for the delivery of mail in the UK and around the world. BFPO moved from its ...
(BFPO) provides a postal service to HM Forces separate from that provided by Royal Mail in the United Kingdom, with BFPO addresses used for the delivery of mail in the UK and around the world. BFPO codes such as "BFPO 801" serve the same function as postal codes for civilian addresses, with the last line of the address consisting of "BFPO" followed a space and a number of 1 to 4 digits. For consistency with the format of other UK addresses, in 2012 BFPO and Royal Mail jointly introduced an optional alternative postcode format for BFPO addresses, using the new non-geographic postcode area "BF" and the notional
post town A post town is a required part of all postal addresses in the United Kingdom and Ireland, and a basic unit of the postal delivery system.Royal Mail, ''Address Management Guide'', (2004) Including the correct post town in the address increases ...
"BFPO". Each BFPO number is assigned to a postcode in the standard UK format, beginning "BF1". The database was released commercially in March 2012 as part of the Royal Mail Postal Address File (PAF). A postcode is not required if the traditional "BFPO nnnn" format is used.


Non-geographic codes

Most postcodes apply to a geographic area but some are used only for routing and cannot be used for navigation or estimating distances. They are often used for
direct marketing Direct marketing is a form of communicating an offer, where organizations communicate directly to a pre-selected customer and supply a method for a direct response. Among practitioners, it is also known as ''direct response marketing''. By ...
and
PO box A post office box (commonly abbreviated as P.O. box, or also known as a postal box) is a uniquely addressable lockable box located on the premises of a post office. In some regions, particularly in Africa, there is no door to door delivery ...
es. Non-geographic postcode area BX is used solely for non-geographic addresses, with codes independent of the location of the recipient. Some postcode sectors or districts are set aside solely for non-geographic postcodes, including EC50, BS98, BT58, BX1–BX9, IM99, M60, N1P, NE99, SA99, SW9, WV99, WV98 and JE4. Also the first two numbers can be from the range 91 to 95 for businesses and a range 96 to 99 for Government departments. The letters HQ for the last two letters could also it most likely is a non-graphical postcode of that Royal Mail holds the mail which a redirection, bulk mail delivery or open and scan to email service is available.
Girobank National Girobank was a British public sector financial institution run by the General Post Office that opened for business in October 1968. It started life as ''National Giro''  then ''National Girobank'' and finally ''Girobank plc'' be ...
's headquarters in
Bootle Bootle (pronounced ) is a town in the Metropolitan Borough of Sefton, Merseyside, England, which had a population of 51,394 in 2011; the wider Parliamentary constituency had a population of 98,449. Historically part of Lancashire, Bootle's ...
used the non-geographic postcode GIR 0AA. There is also a special postcode for letters to Santa/Father Christmas, XM4 5HQ. Many non-geographic postcodes do not appear on Royal Mail's own online postcode finder tool or their Click and Drop online postage printing tool, which can add to confusion when responding to organisations that use such addresses. Likewise, delivery services or couriers other than Royal Mail may not be able to deliver to such non-physical addresses.


Special postcodes

Postcodes A postal code (also known locally in various English-speaking countries throughout the world as a postcode, post code, PIN or ZIP Code) is a series of letters or digits or both, sometimes including spaces or punctuation, included in a postal ...
are allocated by Royal Mail's Address Management Unit and cannot be purchased or specified by the recipient. However, Royal Mail sometimes assigns semi-
mnemonic A mnemonic ( ) device, or memory device, is any learning technique that aids information retention or retrieval (remembering) in the human memory for better understanding. Mnemonics make use of elaborative encoding, retrieval cues, and imag ...
postcodes to high-profile organisations. Prominent examples are: The postcode printed on Business Reply envelopes (which do not require a stamp) often ends with the letters BR.


Operation


Sorting

Postcodes are used to sort letters to their destination either manually, where sorters use labelled frames, or increasingly with letter-coding systems, where machines assist in sorting. A variation of automated sorting uses
optical character recognition Optical character recognition or optical character reader (OCR) is the electronic or mechanical conversion of images of typed, handwritten or printed text into machine-encoded text, whether from a scanned document, a photo of a document, a sc ...
(OCR) to read printed postcodes, best suited to mail that uses a standard layout and addressing format. A long string of "faced" letters (i.e. turned to allow the address to be read) is presented to a keyboard operator at a coding desk, who types the postcodes onto the envelopes in coloured phosphor dots. The associated machine uses the outward codes in these dots to direct bundles of letters into the correct bags for specific delivery offices. With a machine knowledge of the specific addresses handled by each postal walk at each office, the bundles can be further sorted using the dots of the inward sorting code so that each delivery round receives only its own letters. This feature depends upon whether it is cost effective to second-sort outward letters, and tends to be used only at main sorting offices where high volumes are handled. When postcodes are incomplete or missing, the operator reads the post town name and inserts a code sufficient for outward sorting to the post town, where others can further direct it. The mail bags of letter bundles are sent by road, air or train, and eventually by road to the delivery office. At the delivery office the mail that is handled manually is inward sorted to the postal walk that will deliver it; it is then "set in", i.e. sorted into the walk order that allows the deliverer the most convenient progress in the round. The latter process is now being automated, as the roll-out of walk sequencing machines continues.


Integrated Mail Processors

Integrated Mail Processors (IMPs) read the postcode on the item and translate it into two phosphorus barcodes representing the inward and outward parts of the postcode, which the machines subsequently print and read to sort the mail to the correct outward postcode. Letters may also be sequentially sorted by a Compact Sequence Sorter (CSS) reading the outward postcode in the order that a walking postman/woman will deliver, door to door. On such items the top phosphorous barcode is the inward part of the code, the bottom is the outward. IMPs can also read RM4SCC items, as used in Cleanmail, a different format to the above.


Mailsort and Walksort

A newer system of five-digit codes called
Mailsort Mailsort was a five-digit address-coding scheme used by the Royal Mail (the UK's postal service) and its business customers for the automatic direction of mail until 2012. Mail users who could present mail sorted by Mailsort code and in quantities ...
was designed for users who send "a minimum of 4,000 letter-sized items". It encodes the outward part of the postcode in a way that is useful for mail routing, so that a particular range of Mailsort codes goes on a particular plane or lorry. Mailsort users are supplied with a database to allow them to convert from postcodes to Mailsort codes and receive a discount if they deliver mail to the post office split up by Mailsort code. Users providing outgoing mail sorted by postcode receive no such incentive since postcode areas and districts are assigned using permanent mnemonics and do not therefore assist with grouping items together into operationally significant blocks. Walksort was discontinued in May 2012.


Listings and availability

There are approximately 1.7 million postcodes in the United Kingdom, the Channel Islands and the Isle of Man. Each postcode is divided by a space into two parts. As mentioned above, the first part starts with the postcode area and ends with the postcode district. The second part begins with a single digit, which indicates the postcode sector, and ends with the postcode unit. Postcode areas are also divided into several
post town A post town is a required part of all postal addresses in the United Kingdom and Ireland, and a basic unit of the postal delivery system.Royal Mail, ''Address Management Guide'', (2004) Including the correct post town in the address increases ...
s, which predate the introduction of postcodes, with the
London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
post town uniquely covering more than one postcode area. As of June 2016, there are 124 postcode areas, 2,987 postcode districts, 11,192 postcode sectors, and 1,500 post towns. Addresses receiving large volumes of mail are each assigned separate "large user" postcodes. But most postcodes are shared by several neighbouring properties, typically covering about 15 addresses.


Life-cycle of postcodes

There are also significant numbers of discontinued (terminated) codes. Each month some 2,750 postcodes are created and 2,500 terminated.


Postcode Address File (PAF)

The Address Management Unit of Royal Mail maintains an official database of UK postal addresses and postcodes in its
Postcode Address File The Postcode Address File (PAF) is a database that contains all known "delivery points" and postcodes in the United Kingdom. The PAF is a collection of over 29 million Royal Mail postal addresses and 1.8 million postcodes. It is available i ...
(PAF), which is made available under licence for a fee regulated by
Ofcom The Office of Communications, commonly known as Ofcom, is the government-approved regulatory and competition authority for the broadcasting, telecommunications and postal industries of the United Kingdom. Ofcom has wide-ranging powers acros ...
. The PAF is commercially licensable and is often incorporated in address management software packages. The capabilities of such packages allow most addresses to be constructed solely from the postcode and house number. By including the map references of postcodes in the address database, the postcode can be used to pinpoint a postcode area on a map. PAF is updated daily. On its website, Royal Mail publishes summary information about major changes to postcode sectors and postal localities (including post towns). Individual postcodes or postal addresses can be found using Royal Mail'
Postcode and Address Finder
website, but this is limited to 50 free searches per user per day.


Code-Point Open

A complete list of all current Great Britain postcodes, known as Code-Point Open, has been made available online (since 1 April 2010) by Ordnance Survey. Under the government's OS OpenData initiative, it is available for re-use without charge under an attribution-only licence. The Code-Point Open list includes median coordinates for each postcode but excludes postcodes in Northern Ireland and the Crown dependencies. Unlike the PAF products provided by Royal Mail, the Code-Point Open list does not include postal address text.


ONS Postcode Directory and National Statistics Postcode Lookup

The
Office for National Statistics The Office for National Statistics (ONS; cy, Swyddfa Ystadegau Gwladol) is the executive office of the UK Statistics Authority, a non-ministerial department which reports directly to the UK Parliament. Overview The ONS is responsible for t ...
also produces postcode directories, under similar licence terms to the OS product. Both the ONSPD and NSPL contain Northern Ireland postcodes, with centroid coordinates in the
OSI OSI may refer to: Places * Osijek Airport (IATA code: OSI), an airport in Croatia * Ősi, a village in Veszprém county, Hungary * Oši, an archaeological site in Semigallia, Latvia * Osi, a village in Ido-Osi, Ekiti State, Nigeria * Osi, Ekiti ...
grid as opposed to the OSGB grid, although Northern Ireland postcodes are subject to a more restrictive licence permitting internal business use only. Postcodes for the Crown Dependences are also included, without co-ordinates. A further difference is that non-current postcodes and dates of introduction and withdrawal of postcodes are included.


Other uses

While postcodes were introduced to expedite the delivery of mail, they are useful tools for other purposes, particularly because codes are very fine-grained and identify just a few addresses. Among these uses are: * With
satellite navigation A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high pr ...
systems, to navigate to an address by street number and postcode * By life insurance companies and pension funds to assess longevity for pricing and reservingRichards, S. J. Applying survival models to pensioner mortality data, British Actuarial Journal
* By other types of insurance companies to assess premiums for motoring/business/domestic policies * To determine catchment areas for school places or doctors' surgeries *Finding the nearest branch of an organisation to a given address. A computer program uses the postcodes of the target address and the branches to list the closest branches in order of distance as the crow flies (or, if used in conjunction with street-map software, by road distance). This can be used by companies to inform potential customers where to go, by
job centre An employment agency is an organization which matches employers to employees. In developed countries, there are multiple private businesses which act as employment agencies and a publicly-funded employment agency. Public employment agencies One ...
s to find jobs for job-seekers, to alert people of
town planning Urban planning, also known as town planning, city planning, regional planning, or rural planning, is a technical and political process that is focused on the development and design of land use and the built environment, including air, water, ...
applications in their area, and a great many other applications. The phrase "
postcode lottery In the United Kingdom, the postcode lottery is the unequal provision of services such as healthcare, education and insurance prices depending on the geographic area or postcode. Postcodes can directly affect the services an area can obtain, such ...
" refers to the variation in the availability of services by region, though not always because of postcodes. For these and related reasons, postcodes in some areas have become indicators of social status. Some residents have campaigned to change their postcode to associate themselves with a more desirable area, to disassociate with a poorer area, to reduce insurance premiums or to be associated with an area with a lower
cost of living Cost of living is the cost of maintaining a certain standard of living. Changes in the cost of living over time can be operationalized in a cost-of-living index. Cost of living calculations are also used to compare the cost of maintaining a cer ...
. In all these cases Royal Mail has said that there is "virtually no hope" of changing the postcode, referring to their policy of changing postcodes only to match changes in their operations. Postcode areas rarely align with local government boundaries and a few straddle
England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
's borders with
Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...
and
Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the ...
. This has led to
British Sky Broadcasting Sky UK Limited is a British broadcaster and telecommunications company that provides television and broadband Internet services, fixed line and mobile telephone services to consumers and businesses in the United Kingdom. It is a subsidiary of ...
subscribers receiving the wrong BBC and ITV regions, and newly licensed
radio amateurs An amateur radio operator is someone who uses equipment at an amateur radio station to engage in two-way communication, two-way personal communications with other amateur operators on Frequency, radio frequencies Amateur radio frequency allocatio ...
being given incorrect
call signs In broadcasting and radio communications, a call sign (also known as a call name or call letters—and historically as a call signal—or abbreviated as a call) is a unique identifier for a transmitter station. A call sign can be formally assign ...
.


See also

* List of postcode areas in the United Kingdom *
List of postal codes This list shows an overview of postal code notation schemes for all countries that have postal or ZIP Code systems. List ; Legend * A = letter * N = number * ? = letter or number * CC = ISO 3166-1 alpha-2 country code }) formally. The f ...
(around the world) * ACORN * Address Point *
Postcode lottery In the United Kingdom, the postcode lottery is the unequal provision of services such as healthcare, education and insurance prices depending on the geographic area or postcode. Postcodes can directly affect the services an area can obtain, such ...
*
RM4SCC __NOTOC__ RM4SCC (Royal Mail 4-State Customer Code is the name of the barcode character set based on the Royal Mail 4-State Bar Code symbology created by Royal Mail. The RM4SCC is used for the Royal Mail Cleanmail service. It enables UK postcodes ...
—a machine-readable barcode version of the postcode and delivery point suffix *
Postcode Address File The Postcode Address File (PAF) is a database that contains all known "delivery points" and postcodes in the United Kingdom. The PAF is a collection of over 29 million Royal Mail postal addresses and 1.8 million postcodes. It is available i ...


References

{{DEFAULTSORT:Postcodes In The United Kingdom
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
1959 introductions
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
Postal history of the United Kingdom
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...