In the United Kingdom and the Crown Dependencies, telephone numbers 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.
Telephone numbers are of variable length. Local numbers are supported from landlines. Numbers can be dialled with a '0'-lead prefix that denotes either a geographical region or another service. Mobile phone numbers have distinct prefixes that are not geographic, and are portable between providers.
Structure All mobile numbers, nearly all geographic numbers, and nearly all non-geographic numbers have ten national (significant) digits after the trunk code 0. The overall structure of the UK's National Numbering Plan is: Prefix Service type00 International01 Geographic area codes02 Geographic area codes (introduced in 2000).03 Non-geographic numbers charged at standard geographic area code rates (introduced in 2007)04 Not in use05 Corporate numbering and VoIP services; freephone services (0500) until June 201706 Not in use07 Mobile telephony (071xx–075xx, 07624 and 077xx–079xx), personal numbering (070xx), and pagers (076xx)08 Non-geographic freephone numbers (080x), non-geographic service numbers (084x and 087x)09 Non-geographic service numbers
A short sample of geographic numbers, set out in the officially approved (Ofcom) number groups: NumberLocationLondonCardiffLeedsLeicesterBirminghamLiverpoolDundeeEveshamOxfordBoltonSedberghBrampton
In the United Kingdom, the "area code" was historically referred to as a "subscriber trunk dialling code" (STD code) or a "dialling code". United Kingdom area codes are two, three, four or, exceptionally, five digits long (after the initial zero). Regions with shorter area codes, typically large cities, permit the allocation of more telephone numbers as the local number part has more digits. Local customer numbers are four to eight digits long. The total number of digits is ten or, very rarely, nine.
The code allocated to the largest population is (020) for London. The code allocated to the largest area is (028) for all of Northern Ireland. The UK Numbering Plan also applies to three British Crown dependencies – Guernsey, Jersey, and the Isle of Man – even though they are not part of the UK, these countries are closely related.
Format
Possible number formats for UK telephone numbers are: Number length 10-digit NSN 9-digit NSN 7-digit NSN 6 digits 5 digits 4 digits 3 digits Number formats (01xx xx) xx xxx(01xxx) xxx xxx(01x1) xxx xxxx(011x) xxx xxxx(02x) xxxx xxxx03xx xxx xxxx055 xxxx xxxx056 xxxx xxxx07x xxxx xxxx07xxx xxx xxx0800 xxx xxxx08xx xxx xxxx09xx xxx xxxx (01xx xx) xxxx(01xxx) xx xxx 0800 xxx xxx 0800 11 110845 46 4x118 xxx116 xxx1707014701471147214741475147614771478147915711572999112100101105111119123141155159 195
Number ranges starting 01 can have National Significant Number (NSN) length of 10 or (very rarely) 9 digits. NSN is the number of digits after the leading 0 trunk code or +44 international prefix. The 0800 range can have NSN length as 10, 9, or 7 digits. The 0845 range can have NSN length as 10 or 7 digits. The 0500 range had NSN length as 9 digits only, and was withdrawn from use on 3 June 2017. All other UK numbers have NSN length of 10 digits. There are no telephone numbers in the UK with an NSN length of 8 digits.
Geographic numbers
Standard geographic numbers Geographic telephone numbers in the UK always have nine or ten digits after the 0 trunk code or +44 international dialling prefix.
Four-digit area codes Four-digit area codes have either six-digit subscriber numbers or a mix of five- and six-digit subscriber numbers. (01xxx) xxx xxx
This is the format used by most areas. It has a four-digit area code (after the initial zero) and a six digit subscriber number, and is known as 4+6 format. These area codes were changed by adding a "1" directly after the initial zero as a part of PhONEday in 1995. Just short of 581 areas use this format, and the area codes range from 01200 to 01998. Almost all (01xxx) area codes now have only six-digit subscriber numbers, but a small number of these areas also have some subscriber numbers that are only five digits in length (see next section). 01224 Aberdeen 22 = AB 01244 Chester 24 = CH 01275 Clevedon 27 = BR 01382 Dundee 38 = DU 01387 Dumfries (mixed) 38 = DU Local numbers cannot begin with 3 01452 Gloucester 45 = GL 01472 Grimsby 47 = GR 01473 Ipswich 47 = IP 01429 Hartlepool 42 = HA 01482 Hull 48 = HU 01539 Kendal (mixed) 53 = KE Local numbers cannot begin with 4, 5 or 6 01582 Luton 58 = LU 01642 Teesside or Middlesbrough 64 = MI 01670 Morpeth 67 = MP 01697 Brampton, North West (mixed) 69 = NW Local numbers cannot begin with 3, 4 or 7 01733 Peterborough 73 = PE 01736 Penzance 73 = PE 01772 Preston 77 = PR 01782 Stoke-on-Trent 78 = ST 01792 Swansea 79 = SW 01793 Swindon 79 = SW 01854 Ullapool 85 = UL 01947 Whitby 94 = WH
Six of the four-digit area codes are known as "mixed" areas as they share those four digits with the twelve five-digit area codes. This leads to a restriction as to which initial digits can be used for subscriber numbers within those four-digit area codes, e.g. in the 01387 four-digit area code, subscriber numbers cannot begin with a 3 because 013873 is a separate five-digit area code; likewise in the 01946 four-digit area code, subscriber numbers cannot begin with a 7 because 019467 is a separate five-digit area code. (01xxx) xx xxx
This is used for forty smaller towns which have a mixture of six and five digit local numbers, each type allocated in specific DE blocks*; e.g. in the 01647 area code numbers beginning 24 and 61 have five digits (24xxx and 61xxx; known as 4+5 format) whereas all other DE blocks* within that area code have six digit numbers. The number of places with five digit subscriber numbers and an 01xxx area code has declined rapidly in recent decades. There were 511 ranges allocated across 56 different area codes in January 1998. The Big Number Change removed many, especially in Northern Ireland, and by July 2005 there were only 329 ranges in 42 codes. By April 2010 this had reduced to 324 ranges in 40 codes, with still the same number in November 2012. The 40 area codes are listed in the table below.
*A DE block is a block of numbers where (taking the area code and the subscriber number together) the initial 0 and the next six digits after it are the same for all the subscriber numbers in the block.
(These area codes, like many others, were changed by adding a "1" directly after the initial zero as a part of PhONEday in 1995.)
01204 Bolton 20 = BO 61–64 01208 Bodmin 20 = BO 72–79 01254 Blackburn 25 = BL 51–57, 59 01276 Camberley 27 = CR 20–29, 31–38, 61–66 01297 Axminster 29 = AX 20–24, 32–35 01298 Buxton 29 = BX 22–28, 70–74, 77–79, 83–85 01363 Crediton 36 = CN 82–85 01364 Ashburton, Devon 36 = DN 72, 73 01384 Dudley 38 = DU 70, 74–79 01386 Evesham 38 = EV 40, 41, 45, 47–49 01404 Honiton 40 = HO 41–47 01420 Alton, Hampshire 42 = HA 22, 23, 80–89 01460 Chard, Ilminster 46 = IM 30, 52–55, 57, 61–68, 72–78 01461 Gretna 46 = GN 40 01480 Huntingdon 48 = HU 52 01488 Hungerford 48 = HU 71–73 01524 Lancaster (mixed) 52 = LA 32–37, 39, 60–69 Local numbers cannot begin with 2 01527 Redditch 60–69 01562 Kidderminster 56 = KM 60, 66–69 01566 Launceston 56 = LN 86 01595 Lerwick 56 = LW 86 01606 Northwich, Winsford 60 = NO 40–49, 74–77, 79 01629 Matlock 62 = MA 55–57 01635 Newbury 63 = NE 30–39, 40–49 01647 Moretonhampstead 64 = MH 24, 61 01659 Sanquhar, Nithsdale 65 = NL 50, 58, 66, 67, 74 01695 Skelmersdale/Ormskirk 50–54 01726 St Austell 72 = SA 61, 63–69, 70–77 01744 St Helens 74 = SH 20–29 01750 Selkirk 75 = SK 20–23, 32, 42, 52, 62, 76, 82 01768 Penrith (mixed) 76 = PN 882, 883, 884, 886, 887, 888 Local numbers cannot begin with 3, 4 or 7 01827 Tamworth 82 = TA 50–59, 60–69 01837 Okehampton 52–55, 82, 83, 89 01884 Tiverton 88 = TV 32–35, 38 01900 Workington 90 = WO 61–68, 85 01905 Worcester 90 = WO 20–29 01935 Yeovil 93 = YE 83 01946 Whitehaven (mixed) 94 = WH 61–68 Local numbers cannot begin with 7 01949 Whatton 94 = WH 20, 21, 81 01963 Wincanton 96 = WN 23, 31–34 01995 Garstang, Wyre 99 = WY 61
Three-digit area codes Three-digit area codes are generally used for the UK's largest cities and conurbations (with the exception of London) and always have seven-digit subscriber numbers and always begin 011x or 01x1.
(01x1) xxx xxxx
This is the geographic number format for the first round of five large cities moved to all figure dialling in the 1960s, and subsequently also used in the metropolitan county of Tyne and Wear, eastern County Durham and south-eastern Northumberland from the 1980s onwards. These six areas have a three-digit area code matching the pattern 1x1 (after the initial zero) and a seven digit subscriber number, and this is known as 3+7 format. These area codes were changed by adding a "1" directly after the initial zero as a part of PhONEday in 1995. CodeGeographical areaFormer code(s) 0121 Birmingham 021 (2 = B) 0131 Edinburgh 031 (3 = E) 0141 Glasgow 041 (4 = G) 0151 Liverpool 051 (5 = L) 0161 Manchester 061 (6 = M) 0171 Used for Inner London from 1990 until 2000 0181 Used for Outer London from 1990 until 2000 0191 County of Tyne and WearEastern County DurhamSouth-eastern Northumberland 091 (9 = tYne).Before 1982:0385 (Durham; 38 = DU)0632 (North Tyneside/Newcastle; 63 = NE)0783 (Sunderland; 78 = SU)0894 (South Tyneside; 89 = TY).
(011x) xxx xxxx
This is the geographic number format for the second round of large cities and towns moved to brand-new three-digit area codes. Five of these were moved in 1995 as a part of PhONEday, with Reading then following a year later. At the time of the change, an extra digit was added to the subscriber number. These six areas have a three-digit area code matching the pattern 11x, with a seven-digit subscriber number, and this is known as 3+7 format. The first three digits of the local number identifies a small area within the town or city. The former Reading area code had already been changed once, by adding a "1" directly after the initial zero as a part of PhONEday in 1995. CodeGeographical areaFormer code(s) 0113 Leeds 0532 (53 = LE) 0114 Sheffield 0742 (74 = SH) 0115 Nottingham 0602 (60 = NO) 0116 Leicester 0533 (53 = LE) 0117 Bristol 0272 (27 = BR) 0118 Reading 0734, then 01734 (73 = RE)
Two-digit area codes Two-digit area codes always have eight-digit subscriber numbers and always begin 02. (02x) xxxx xxxx
This is the newest geographic number format. It is used for the third round of changes for large cities and for Northern Ireland, and was formed as a part of the Big Number Change in 2000. The new area code is much shorter than the old one, and begins 02 unlike the previous 01 area codes. Numbers consist of a two-digit area code matching the pattern 02x, and an eight-digit subscriber number, and this is known as 2+8 format. Numbers in these five areas are commonly misquoted, e.g. London incorrectly as 0207 or Cardiff incorrectly as 02920.
The first four digits of the local number identifies a small area within the town, city or region. At the time of the change, the subscriber part of the number gained an extra digit in London, those in Northern Ireland gained two or three digits, and the subscriber part of the number in the other areas gained two digits. All of these areas were also subject to a previous code change, one that added a "1" directly after the initial zero as a part of PhONEday in 1995.