Last updated

United Kingdom adm location map.svg
Red pog.svg
United Kingdom area code for London
National calling020
International calling+44 20
Active since 1 June 1999 [notes 1]
Previous code(s)0171, 0181
Earlier code(s)01; 071, 081
Number format020 xxxx xxxx
020 UK dial code area - 2007.png Approximate coverage of 020 code (red), compared to Greater London boundary (black)
Location of Tristan da Cunha
Area served Bushey Heath
Thames Ditton
Tristan da Cunha
List of United Kingdom codes

020 is the national dialling code for London in the United Kingdom. All subscriber numbers within the area code consist of eight digits and it has capacity for approaching 100 million telephone numbers. The code is used at 170 telephone exchanges in and around Greater London as part of the largest linked numbering scheme in the United Kingdom. In common with all other British area codes the initial '0' is a trunk prefix that is not required when dialling London from abroad.


The 020 area code fully replaced older area codes for London on 22 April 2000, following multiple telephone number changes during the 1990s. [notes 1]

As is the case for other codes in the UK, the 020 area code may also be used for services without any physical presence in the area, such as private networks or virtual numbering. [1] As one such user is the Foreign and Commonwealth Office Telecommunications Network, provided by Global Crossing, 020 is also one of the dialling codes used for telephone services on the remote South Atlantic island of Tristan da Cunha. [2]


London telephone area

Before the introduction of national dialling codes, the area now served by 020 had a large multiple telephone exchange system, called the London telephone area. The first exchange in this area, Central, was opened in the City of London on 1 March 1902. [3] The Director telephone system was developed so that subscribers in London could call one another in a linked numbering scheme regardless of whether they were on a manual local exchange or an automatic one.

In 1927, Holborn, the first Director automatic exchange in London, was cut over to the new system at midnight on Saturday 12 November. Because it was mainly a business exchange, most subscribers did not use the new system until Monday 14 November. The successful changeover was delayed by subscribers' unfamiliarity with dialling. Bishopgate and Sloane exchanges followed in six weeks, after which came Western and Monument exchanges. Because the London area contained 80 exchanges, complete conversion took many years. [4] [5]

By 1934, the London telephone area comprised all 147 exchanges within 12.5 miles (20.1 km) of Oxford Circus. [6] By 1950, the London Director system had 75 exchanges within a 5-mile (8.0 km) radius of Oxford Circus and a further 65 in the 5–10-mile (8–16 km) belt. In Greater London (in other words, within 20 miles (32 km) of Oxford Circus), there were 237 exchanges. [7] In January 1956 a new director exchange – "SKYport" – was opened at London Heathrow Airport. [8]

Exchange codes

From 1922, the first three digits of a seven-digit subscriber number in other words, the local exchange codes were represented with letters by way of a mnemonic. Each three-character code corresponded to an exchange within the London telephone area. The subscriber numbers were written, for example, as "ABBey 1234" and "WIMbledon 1234" or "ABB 1234" and "WIM 1234". By 1965, there were 350 local exchanges in London and the number of permutations that could be used for exchange names had been exhausted. [9] With the change to all-figure dialling in 1966, the system of mnemonics was withdrawn and the three-digit local exchange codes of many subscribers were altered. The old codes continued to work in parallel with new codes until January 1970, when the "ANN: All-figure Numbers Now" advertising campaign prompted callers to use only the new codes. [10] The transition to all-figure dialling allowed the codes to be grouped into eight sectors; all exchanges within 6 kilometres (3.7 mi) of the centre of London formed the Central sector and the other sectors radiated from it. [11]

SectorLocal exchange code prefixes
Central21–28, 32, 35, 37, 38, 40, 43, 48, 49, 58, 60, 61, 62, 63, 70, 72, 73, 79, 82, 83, 92, 93
East47, 50, 51, 52, 53, 55, 59, 98
South64, 65, 66, 67, 68, 76, 77
South East29, 30, 31, 46, 69, 85
South West33, 39, 54, 78, 87, 94, 97
North34, 36, 44, 80, 88
North West20, 42, 45, 86, 90, 95, 96
West56, 57, 74, 75, 84, 89, 99

The first three digits of a subscriber number continued to indicate the exchange to which the number belonged; for example, "222 1234" was in Westminster (Central Sector) and "946 1234" in Wimbledon (South West Sector). [notes 2] More than one local exchange code was usually overlaid for each area, so all Wimbledon numbers did not necessarily begin "946". Subscriber numbers changed to eight digits in 2000 when an additional 7 or 8 was added to each local exchange code (for example, "7222 1234" in Westminster and "8946 1234" in Wimbledon).

STD code

Example telephone number
1959–1966STD codes introduced01-WIM 0123
1966–1990 All-figure dialling 01-946 0123
1990–1995Area code split081-946 0123
1995–2000 PhONEday 0181 946 0123
2000–present Big Number Change 020 8946 0123

The STD code 01 was assigned to the London telephone area on 6 April 1959 as part of preparations for subscriber trunk dialling. [12] For the next thirty years, "01" became synonymous with the capital. [13] Until May 1990, the 01 code covered the same area as the current 020 code and had capacity for fewer than 10 million telephone numbers. [14]

In May 1990, the 01 code was abandoned and the area divided between 071 which covered exchanges in the Central sector and 081, which covered all other sectors. Exceptionally, two exchanges in the East sector [notes 3] covering the London Docklands redevelopment area were assigned the 071 code. [15] The anticipation that the code associated with central districts would be more prestigious than the other associated with the outer suburbs [16] was used as a plot device in the Essex-based TV comedy series Birds of a Feather . [17] At the time of the split, there were five local exchange codes assigned to Mercury Communications [notes 4] and numbers in these ranges could be assigned to either code. [15] This area code split doubled the potential capacity. [14] In 1995, on "PhONEday", the codes changed again, to 0171 and 0181.

Sequence of code changes. History of London STD codes.svg
Sequence of code changes.

The split into two area codes only lasted a decade. As part of the Big Number Change on 22 April 2000, the 0171 and 0181 codes were replaced with 020, following a period of dual-running that began on 1 June 1999 when the new 020 code was activated and ended on 14 October 2000 when the old 0171 and 0181 codes were finally ceased. The 22 April 2000 change also affected subscriber local numbers which gained an extra digit. "0171-xxx xxxx" numbers changed to "(020) 7xxx xxxx", while "0181-xxx xxxx" numbers became "(020) 8xxx xxxx". As a result of this history, there is now a widespread misconception that 0207 and 0208 are the dialling codes for parts of London. [18] This was exacerbated when local numbers beginning 3 started to be issued.

The reunification under a single code created capacity for approaching 100 million telephone numbers [14] and, starting in 2005, subscriber numbers beginning with the digit "3" were issued alongside those beginning "7" and "8". [14] In August 2019, Ofcom announced that subscriber numbers beginning with the digit "4" will also be introduced. [19]

Charge group

The London telephone area operated as a single group for charging purposes in which all calls were priced at local rate. Additionally, as was usual, calls to and from the adjacent charge groups were charged as local. [notes 5]


The code serves a roughly circular area with a radius of 20 kilometres (12 mi) from the centre of London. The Greater London boundary varies from 17 kilometres (11 mi) to 32 kilometres (20 mi) from the centre and consequently some outer districts are covered by adjacent codes and in some places the 020 code extends beyond the Greater London boundary. The code covers an area larger than the London post town where letters addressed to "LONDON" are delivered.

The City of London and at least some part of all 32 London boroughs are within the 020 area code. There are six exchanges outside Greater London that use the 020 code. [notes 6] Communities outside Greater London that are within the code are Buckhurst Hill, Chigwell, Loughton and Sewardstone in Essex; Borehamwood, Bushey, Carpenders Park, Elstree and South Oxhey in Hertfordshire; and Ewell, Molesey, Thames Ditton and Whyteleafe in Surrey.

There are eighteen exchanges within Greater London that do not use the 020 code. [notes 7] The six boroughs that have significant areas within other codes are Bexley, partly within the Dartford (01322) code; Bromley, partly within the Orpington (01689) and Westerham (01959) codes; Croydon, partly within the Orpington (01689) and Redhill (01737) codes; Enfield, partly within the Waltham Cross (01992) code; Havering, mostly within the Romford (01708) code; and Hillingdon, partly within the Uxbridge (01895), Slough (01753) and Watford (01923) codes.

Number allocation

With the introduction of the (020) area code, as part of the Big Number Change, subscriber numbers were changed from 7-digits (xxx xxxx) to 8-digits (xxxx xxxx). This allowed new ranges of numbers to be issued. Under the National Telephone Numbering Plan the code operates with the following sub-ranges:

0xxx xxxx 1xxx xxxxnational dialling only
2xxx xxxxreserved for future use
3xxx xxxxnew local numbers issued after move to 020 (since 2005)
4xxx xxxx new local numbers issued after move to 020 (since 2019)
5xxx xxxx 6xxx xxxxreserved for future use
70xx xxxx 71xx xxxxnew local numbers issued after move to 020 (since 2000)
72xx xxxx 73xx xxxx 74xx xxxx 75xx xxxx  76xx xxxx 77xx xxxx 78xx xxxx 79xx xxxx local numbers transferred from 0171
80xx xxxx 81xx xxxxnew local numbers issued after move to 020 (since 2000)
82xx xxxx 83xx xxxx 84xx xxxx 85xx xxxx  86xx xxxx 87xx xxxx 88xx xxxx 89xx xxxxlocal numbers transferred from 0181
9xxx xxxxreserved for future use

In 2006 59% of numbers within the 020 code were allocated to BT. [20] The area code is not subject to number conservation and the regulator Ofcom does not restrict the size of number blocks that are allocated. [21]


  1. 1 2 020 could be used from 1 June 1999 and the previous 0171 and 0181 codes could no longer be used from 22 April 2000.
  2. The numerical codes for Westminster and Wimbledon did not change when all-figure dialling was introduced because the first two digits of their exchange codes corresponded to the sectors they became part of.
  3. Albert Dock and Poplar exchanges were not in the Central sector but were included in the 071 code.
  4. Exchange codes 528, 895, 945, 975 and 982 were assigned to Mercury Communications.
  5. Calls to London from each of the 01322, 01372, 01689, 01707, 01708, 01727, 01737, 01753, 01784, 01883, 01895, 01923, 01932, 01959 and 01992 area codes were charged at local rate, as were calls from London to each of those area codes.
  6. Bushey Heath, Elstree, Ewell, Hainault (Chigwell), Loughton and Thames Ditton exchanges are outside Greater London.
  7. Biggin Hill, Crayford, Denham, Downland, Erith, Farnborough, Harefield, Hornchurch, Ingrebourne, Lodge Hill, Northwood, Orpington, Rainham, Romford, Ruislip, Slade Green, Upminster, Uxbridge and West Drayton do not use the 020 code.

Related Research Articles

A toll-free telephone number or freephone number is a telephone number that is billed for all arriving calls instead of incurring charges to the originating telephone subscriber. For the calling party, a call to a toll-free number from a landline is free of charge.

Subscriber trunk dialling (STD), also known as subscriber toll dialing, is a telephone numbering plan feature and telecommunications technology for the dialing of trunk calls by telephone subscribers without the assistance from switchboard operators.

A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reachable by a system of destination code routing. Telephone numbering plans are defined in each of the administrative regions of the public switched telephone network (PSTN) and in private telephone networks.

Telephone numbers in the United Kingdom

Telephone numbers in the United Kingdom are administered by the Office of Communications (Ofcom). For this purpose, Ofcom established a telephone numbering plan, known as the National Telephone Numbering Plan, which is the system for assigning telephone numbers to subscriber stations.

All-figure dialling was a telephone numbering plan introduced in the United Kingdom starting in 1966 that replaced the traditional system of using initial letters of telephone exchange names as the first part of a telephone number. The change affected subscriber numbers in the cities of Birmingham, Edinburgh, Glasgow, Liverpool, London and Manchester which used the Director telephone system.

In Argentina, area codes are two, three, or four digits long. Local customer numbers are six to eight figures long. The total number of digits is ten, for example, phone number (11) 1234-5678 for Buenos Aires is made up of a 2-digit area code number and an 8-digit subscriber's number, while (383) 123-4567 would be an example of a Catamarca number.

The Big Number Change addressed various issues with the telephone dialling plan in the United Kingdom, during the late-1990s and early-2000s.

Telephone numbers in Singapore Wikipedia list article

Telephone numbers in Singapore, also known as the National Numbering Plan, are regulated by the Info-communications Media Development Authority (IMDA). Due to the small geographical size of Singapore, there are no area or trunk codes; all numbers belong to one numbering area, and thus come in the same 8-digit format. Numbers are categorised based on the first digit, thus providing ten possible categories, of which six are currently in use and the remaining four reserved for future usage.

A linked numbering scheme (LNS) is a dialing procedure in effect in a service area within which call routing between adjacent exchanges does not require a dialing code. The term is only used in the United Kingdom, but not in the North American Numbering Plan.

Widespread UK telephone code misconceptions, in particular brought on by the Big Number Change in 2000, have been reported by regulator Ofcom since publication of a report it commissioned in 2004.

PhONEday 1995 day in which UK telephones were renumbered

PhONEday was a change to the telephone dialling plan in the United Kingdom on 16 April 1995. It changed geographic area codes and some telephone numbers. In most areas, a "1" was added to the dialling code after the initial zero. In Bristol, Leeds, Leicester, Nottingham and Sheffield, the area codes were replaced with new codes and the subscriber numbers gained an extra digit. The PhONEday changes also made provision for new ranges of subscriber numbers in those five cities. A £16m advertising campaign, and an eight-month period of parallel running during which old and new codes were active, preceded the change. PhONEday followed a change made in May 1990, when the old London area code 01 had been released from use, permitting all United Kingdom geographic numbers to begin with this prefix. Originally planned in 1991 to take place in 1994, in 1992 the change was postponed until the Easter Sunday bank holiday in 1995.

Telephone numbers in Germany Wikipedia list article

The regulation of telephone numbers in Germany is the responsibility of the Federal Network Agency of the German government. The agency has a mandate to telecommunications in Germany and other infrastructure systems.

Telephone numbers in India Wikipedia list article

Telephone numbers in India are administered under the National Numbering Plan of 2003 by the Department of Telecommunications of the Government of India. The numbering plan was last updated in 2015. The country code "91" was assigned to India by the International Telecommunication Union in the 1960s.

The Lisburn telephone exchange code refers to the former 01846 area code, which until the 2000 Big Number Change, served Lisburn, Aghalee, Moira, Hillsborough, Dromore, Maze, Stoneyford and Baillies Mills, all of which are in Northern Ireland, a constituent part of the United Kingdom. This area gained 92 and changed to eight digit numbers, under the new 028 area code.

The national conventions for writing telephone numbers vary by country. While international standards exist in the form of the International Telecommunication Union sector ITU-T issued recommendation E.123, national telephone numbering plans define the format and length of telephone numbers assigned to telephones.


0114 is the national dialling code for Sheffield in the United Kingdom. The area it serves includes almost all of the City of Sheffield and some adjacent areas. When STD codes were first introduced, Sheffield was assigned the mnemonic 0SH2, later changing to the corresponding numbers upon the introduction of All-Figure Dialling in the area. Instead of the expected 01742 code, Sheffield's area code changed to the current 0114 code on 16 April 1995, along with 4 other cities in England, as part of PhONEday. All subscriber numbers within the area code consist of seven digits. The code is used at several telephone exchanges as part of a linked numbering scheme. In common with all other British area codes the initial '0' is a trunk prefix that is not required when dialling Sheffield from abroad.

Ranges for fictitious telephone numbers are common in most telephone numbering plans. One of the main reasons these ranges exist is to avoid accidentally using real phone numbers in movies and television programs because of viewers frequently calling the numbers used. In North America, the area served by the North American Numbering Plan (NANPA) system of area codes, fictitious telephone numbers are usually of the form (XXX) 555-xxxx. The use of 555 numbers in fiction, however, led a desire to assign some of them in the real world, and some of them are no longer suitable for use in fiction. Other areas have different fictitious telephone numbers.


01708 is the national dialling code for Romford in the United Kingdom. The area it serves includes almost all of the London Borough of Havering and some adjacent areas. When STD codes were first introduced, Romford was assigned 0708 and 0402 was used for the rest of the current code area. After a sequence of changes in the early 1990s, culminating with PhONEday, the current 01708 code became active on 16 April 1995. All subscriber numbers within the area code consist of six digits. The code is used at eight telephone exchanges as part a linked numbering scheme. In common with all other British area codes the initial '0' is a trunk prefix that is not required when dialling Romford from abroad.

Telephone numbers in the United Kingdom have a flexible structure that reflects their historical demands, starting from many independent companies through a nationalised near-monopoly, to a system that supports many different services, including cellular phones, which were not envisaged when the system was first built. Numbers evolved in a piecemeal fashion, with numbers initially allocated on an exchange-by-exchange basis for calls connected by manual operators. Subscriber numbers reflected demand in each area, with single digit telephone numbers in very rural areas and longer numbers in cities.


  1. "The National Telephone Numbering Plan" (PDF). ofcom.org.uk. 4 January 2021.{{cite web}}: CS1 maint: url-status (link)
  2. "Global Crossing extends FCO network to Tristan da Cunha" . Retrieved 14 August 2015.
  3. "Events in Telecommunications History: 1902". British Telecommunications PLC. Archived from the original on 12 December 2013.
  4. The Times (London), 1927; 14 November p9 & 16 November p9
  5. Chapuis & Joel (2003). 100 Years of Telephone Switching: Manual and Electromechanical Switching (1878–1960s) Pt. 1. IOS Press.
  6. "Reduced Charges" (PDF). General Post Office. 1934. Archived (PDF) from the original on 14 December 2013.
  7. Telephony: A detailed exposition of the telephone exchange system of the British Post Office by J Atkinson pp373,402 (1950 reprinted 1972, Pitman, London) ISBN   0 273 43181 1.
  8. "Brevites". Flight and Aircraft Engineer. 6 January 1956. Archived from the original on 12 December 2013.
  9. A R Valdar (2008). Understanding telecommunications networks. Institution of Engineering and Technology. pp. 256–8.
  10. "Selling the network". Connected Earth. Archived from the original on 12 December 2013.
  11. A R Valdar (2008). Understanding telecommunications networks. Institution of Engineering and Technology. p. 259.
  12. "Events in Telecommunications History: 1959". British Telecommunications PLC. Archived from the original on 14 October 2009.
  13. For example, in the name of the cultural show 01-for London , broadcast by Thames Television between 1987 and 1990 ( "BFI Film & TV Database: 01-For London". Archived from the original on 5 September 2011. Retrieved 25 September 2012.).
  14. 1 2 3 4 Ofcom (6 October 2004). "New Telephone Numbers for London" (PDF). Office of Communication. Archived (PDF) from the original on 26 May 2011.
  15. 1 2 "How to use the new codes" (PDF). British Telecom. Archived (PDF) from the original on 13 December 2013.
  16. "London Will Divide Its Telephone Prefix, Fraying Composure". The New York Times. 6 May 1990. Archived from the original on 28 August 2010.
  17. "Brief Encounter". Birds of a Feather. Series 2. Episode 14. 18 October 1990. BBC One.
  18. Ofcom. "Telephone numbers – the facts and figures | (Boxout) Is it (020) 7 or 0207?". Office of Communication. Archived from the original on 30 August 2009. Retrieved 22 August 2009.
  19. de Peyer, Robin (30 August 2019). "London to get 10million new landline numbers with launch of new dialling code". Evening Standard . Retrieved 30 August 2019.
  20. "Select Committee on London Local Authorities Bill Minutes of Evidence: Evidence Session (Sections 4400–4499)". Parliamentary Debates (Hansard) . House of Lords. 28 March 2006. Archived from the original on 22 April 2006.
  21. Ofcom (8 April 2010). "Conserving geographic numbers". Statement. Office of Communication. Archived from the original on 11 November 2010.