The Big Number Change was an update of telephone dialling codes in the UK in response to the rapid late-1990s growth of telecommunications and impending exhaustion of numbers. The change greatly expanded the pool of available numbers while helping to retain 'local dialling' (the ability to dial local numbers directly, without needing to dial an area code first). The change affected the dialling codes assigned to Cardiff, Coventry, London, Northern Ireland, Portsmouth and Southampton, culminating in a large switch on 22 April 2000. In addition to new area/city codes for many parts of the UK, the switch was also coupled with a move to eight-digit local numbers, the adjustment of all mobile phone numbers in the UK to the 07 prefix and the alteration of many non-geographic codes to the new 08 range.
Contents |
| Area | Before BNC | After BNC |
|---|---|---|
| Inner London | (0171) xxx xxxx | (020) 7xxx xxxx |
| Outer London | (0181) xxx xxxx | (020) 8xxx xxxx |
| Portsmouth | (01705) xxxxxx | (023) 92xx xxxx |
| Southampton | (01703) xxxxxx | (023) 80xx xxxx |
| Coventry | (01203) xxxxxx | (024) 76xx xxxx |
| Cardiff | (01222) xxxxxx | (029) 20xx xxxx |
Note Under the change the two London areas were reunified under the single (020) code.[1] New numbers beginning with 7, 8 or (later) 3 were allocated regardless of location.
All of the above areas now have an eight-digit local number, in place of their previous six or seven-digit local number. For a short while you could use either number for local dialling, but local access to the old, shorter, numbers was switched off after a few months of parallel running.
In London, new 70xx xxxx, 71xx xxxx, 80xx xxxx, and 81xx xxxx numbers became available for general use. These began to be allocated anywhere in London, with no regard for the 1990-2000 inner/outer London geographical split.
In all of the other areas, new BC0x xxxx and BC1x xxxx numbers became available for general use at the same time (where BC is '76' in Coventry, '20' in Cardiff, etc).
| Area | Before BNC | After BNC | Actual county (if different) |
|---|---|---|---|
| Ballycastle | (012657) xxxxx | (028) 207x xxxx | |
| Martinstown | (012667) xxxxx | (028) 217x xxxx | |
| Ballymena (5-digit) | (01266) xxxxx | (028) 256x xxxx | |
| Ballymena (6-digit) | (01266) xxxxxx | (028) 25xx xxxx | |
| Ballymoney | (012656) xxxxx | (028) 276x xxxx | |
| Larne | (01574) xxxxxx | (028) 28xx xxxx | |
| Kilrea | (012665) xxxxx | (028) 295x xxxx | Londonderry |
| Newry (5-digit) | (01693) xxxxx | (028) 302x xxxx | Partially in Down |
| Newry (6-digit) | (01693) xxxxxx | (028) 30xx xxxx | Partially in Down |
| Armagh | (01861) xxxxxx | (028) 37xx xxxx | |
| Portadown | (01762) xxxxxx | (028) 38xx xxxx | Partially in Down |
| Banbridge | (018206) xxxxx | (028) 406x xxxx | |
| Rostrevor | (016937) xxxxx | (028) 417x xxxx | |
| Kircubbin | (012477) xxxxx | (028) 427x xxxx | |
| Newcastle | (013967) xxxxx | (028) 437x xxxx | |
| Downpatrick | (01396) xxxxxx | (028) 44xx xxxx | |
| Enniskillen | (01365) xxxxxx | (028) 66xx xxxx | |
| Lisnaskea | (013657) xxxxx | (028) 677x xxxx | |
| Kesh | (013656) xxxxx | (028) 686x xxxx | |
| Coleraine (6 digit) | (01265) xxxxxx | (028) 70xx xxxx | |
| Coleraine (5 digit) | (01265) xxxxx | (028) 703x xxxx | |
| Derry | (01504) xxxxxx | (028) 71xx xxxx | |
| Limavady | (015047) xxxxx | (028) 777x xxxx | |
| Magherafelt (6 digit) | (01648) xxxxxx | (028) 79xx xxxx | |
| Magherafelt (5 digit) | (01648) xxxxx | (028) 796x xxxx | |
| Carrickmore | (016627) xxxxx | (028) 807x xxxx | |
| Newtownstewart | (016626) xxxxx | (028) 816x xxxx | |
| Omagh | (01662) xxxxxx | (028) 82xx xxxx | |
| Ballygawley | (016625) xxxxx | (028) 855x xxxx | |
| Cookstown | (016487) xxxxx | (028) 867x xxxx | |
| Dungannon | (01868) xxxxxx | (028) 87xx xxxx | |
| Fivemiletown | (013655) xxxxx | (028) 895x xxxx | |
|
Belfast area |
|||
| Belfast | (01232) xxxxxx | (028) 90xx xxxx | Antrim and Down |
| Bangor | (01247) xxxxxx | (028) 91xx xxxx | Down |
| Lisburn | (01846) xxxxxx | (028) 92xx xxxx | Antrim and Down |
| Ballyclare | (01960) xxxxxx | (028) 93xx xxxx | Antrim |
| Antrim | (01849) xxxxxx | (028) 94xx xxxx | Antrim |
| Saintfield | (01238) xxxxxx | (028) 97xx xxxx | Down |
In Northern Ireland, the situation was more complicated. While the primary reason for the changes was the lack of numbering capacity in Belfast (01232), this was not the only reason. When STD codes were introduced in the 1960s, Northern Ireland was allocated only 14 area codes for 34 charging groups. Normal practice on Great Britain was to allocate one area code per charging group, but as calls to Northern Ireland were national rate from anywhere in GB, it was not seen to be necessary to differentiate between all of them. So, area codes covering multiple charge groups were created; in practice this meant that some areas had longer area codes. For example, while Enniskillen was allocated the area code 0365 (0EK5), Kesh was allocated 03656 and Lisnaskea 03657. As a result, numbers in Enniskillen could not begin with 6 or 7, as this would conflict with those of Kesh or Lisnaskea.
All this meant that while Enniskillen's numbers could be six digits long, Kesh's and Lisnaskea's (and those of other dependent exchanges) could only be five digits, due to the limit of the length of a phone number. This severely restricted capacity in these areas. As a result, at the Big Number Change, all these dependent exchanges were migrated to different numbers than their parent exchanges; in this instance while Enniskillen's 01365 (the 1 coming from PhONEday) was migrated to 028 66, Kesh went from 013656 to 028 686 and Lisnaskea from 013657 to 028 677. This meant that Kesh could expand into the rest of the 028 68xx range.
Note that the new numbering scheme groups numbers together such that the first digit identifies the county in alphabetical order. The exception is the Greater Belfast area where all numbers begin with 9, regardless of the county. The full list of changes for Northern Ireland[2] is as in the table above.
In London, old National Dialling Only 0xx xxxx and 1xx xxxx numbers were migrated to new 0axx xxxx and 1axx xxxx numbers (where 'a' is mostly 0 or 1, so far).
In all of the other areas, old National Dialling Only 0xxxxx and 1xxxxx numbers were migrated to new 0aax xxxx and 1aax xxxx numbers.
These migration from old to new numbers was as follows:[2]
| Area | Old range[3] | New range |
|---|---|---|
| Coventry | 01203 0xxxxx | 024 100x xxxx |
| 01203 1xxxxx | 024 101x xxxx | |
| Cardiff | 01222 0xxxxx | 029 100x xxxx |
| 01222 1xxxxx | 029 101x xxxx | |
| Belfast | 01232 0xxxxx | 028 100x xxxx |
| 01232 1xxxxx | 028 101x xxxx | |
| Southampton | 01703 0xxxxx | 023 110x xxxx |
| 01703 1xxxxx | 023 111x xxxx | |
| Portsmouth | 01705 0xxxxx | 023 100x xxxx |
| 01705 1xxxxx | 023 101x xxxx | |
| London | 0171-0xx xxxx | 020 01xx xxxx |
| 0171-1xx xxxx | 020 11xx xxxx | |
| 0181-0xx xxxx | 020 00xx xxxx | |
| 0181-1xx xxxx | 020 10xx xxxx |
The following changes were made to non-geographic numbering ranges to bring them in the 08xx special services and 09xx premium rate ranges.
| Code | Charging rate | Before BNC | After BNC |
|---|---|---|---|
| 0345 | Local rate | 0345 xxxxxx | 0845 7xx xxxx |
| 0645 | Local rate | 0645 xxxxxx | 0845 9xx xxxx |
| 03745 | National rate | 03745 xxxxxx | 0870 4xx xxxx |
| 0541 | National rate | 0541 xxxxxx | 0870 1xx xxxx |
| 0990 | National rate | 0990 xxxxxx | 0870 5xx xxxx |
| 0321 | Vodafone Freephone | 0321 xxxxxx | 0808 0xx xxxx |
| 0331 | VoData premium rate | 0331 | Unknown |
| 0336 | VoData premium rate | 0336 | Unknown |
| 0338 | Mercury premium rate | 0338 | Unknown |
| 0345 | BT Lo-Call | 0345 xxxxxx | 0845 7xx xxxx |
| 0374 5 | National rate | 03745 xxxxxx | 0870 4xx xxxx |
| 0541 | Mercury AreaCall | 0541 xxxxxx | 0870 1xx xxxx |
| 0632 | Premium rate | 0632 | 09xx |
| 0640 | Mercury premium rate | 0640 | 09xx |
| 0645 | Mercury LocalCall | 0645 xxxxxx | 0845 9xx xxxx |
| 0660 | Mercury premium rate | 0660 | 09xx |
| 0696 | Premium rate | 0696 | 09xx |
| 0696 | Premium rate | 0696 | 09xx |
| 0696 6 | Jersey Telecoms premium rate | 0696 6 | 09xx |
| 0696 8 | Manx Telecoms premium rate | 0696 8 | 09xx |
| 0696 9 | Guernsey Telecoms premium rate | 0696 9 | 09xx |
| 0839 | Mercury premium rate? | 0839 xxxxxx | Unknown |
| 0853 | Premium rate | 0853 | 09xx |
| 0881 | Mercury premium rate | 0881 | 09xx |
| 0890 | Premium rate | 0890 | 09xx |
| 0891 | BT ValueCall | 0891 xxxxxx | 0906 5xx xxxx |
| 0894 | BT premium rate | 0894 | 09xx |
| 0896 | Premium rate | 0896 | 09xx |
| 0897 | BT premium rate | 0897 | 09xx |
| 0898 | BT premium rate | 0898 | 09xx |
| 0930 | Premium rate | 0930 | 09xx |
| 0941 | Premium rate (Pagers?) | 0941 xxxxxx | 07641 xxxxxx |
| 09567 | FleXtel Personal Numbering | 0956 7xxxxx | 070 107x xxxx |
| 0990 | BT NationalCall | 0990 xxxxxx | 0870 5xx xxxx |
| 0991 | Mercury premium rate | 0991 | 09xx |
The 0500 (Mercury FreeCall) code has remained, but no new numbers have been allocated in it since 28 April 2001.
The following changes were made to mobile phone numbering ranges to bring them in the 07xxx mobile numbers range.
| Code | Operator | Before BNC | After BNC |
|---|---|---|---|
| 0370 | Vodafone | 0370 xxxxxx | 07770 xxxxxx |
| 0374 | Vodafone | 0374 xxxxxx | 07774 xxxxxx |
| 0378 | Vodafone | 0378 xxxxxx | 07778 xxxxxx |
| 0385 | Vodafone | 0385 xxxxxx | 07785 xxxxxx |
| 0390 | Orange | 0390 xxxxxx | 07790 xxxxxx |
| 0401 | BT Cellnet | 0401 xxxxxx | 07701 xxxxxx |
| 0402 | BT Cellnet | 0402 xxxxxx | 07702 xxxxxx |
| 0403 | BT Cellnet | 0403 xxxxxx | 07703 xxxxxx |
| 0410 | BT Cellnet | 0410 xxxxxx | 07710 xxxxxx |
| 0411 | BT Cellnet | 0411 xxxxxx | 07711 xxxxxx |
| 0421 | Vodafone | 0421 xxxxxx | 07721 xxxxxx |
| 0441 | Vodafone | 0441 xxxxxx | 07741 xxxxxx |
| 04481 | 04481 xxxxxx | 07781 xxxxxx | |
| 0456 0 | Orange | 0456 0xxxxx | Unknown |
| 0456 1 | Orange | 0456 1xxxxx | Unknown |
| 04624 | 04624 xxxxxx | 07624 xxxxxx | |
| 0467 | Vodafone | 0467 xxxxxx | 07767 xxxxxx |
| 0468 | Vodafone | 0468 xxxxxx | 07768 xxxxxx |
| 0498 | Vodafone | 0498 xxxxxx | 07798 xxxxxx |
| 0585 | BT Cellnet | 0585 xxxxxx | 07885 xxxxxx |
| 0589 | BT Cellnet Vodafone? |
0589 xxxxxx | 07889 xxxxxx |
| 0802 | BT Cellnet | 0802 xxxxxx | 07802 xxxxxx |
| 0831 | Vodafone | 0831 xxxxxx | 07831 xxxxxx |
| 0836 | Vodafone | 0836 xxxxxx | 07836 xxxxxx |
| 0839 | Vodafone | 0839 xxxxxx | 07839 xxxxxx |
| 0850 | BT Cellnet | 0850 xxxxxx | 07850 xxxxxx |
| 0860 | BT Cellnet | 0860 xxxxxx | 07860 xxxxxx |
| 09307 | One-to-One | 0930 7xxxxx | 07930 7xxxxx |
| 0956 | One-to-One | 0956 xxxxxx | 07956 xxxxxx |
| 0958 | One-to-One | 0958 xxxxxx | 07958 xxxxxx |
| 0961 | One-to-One | 0961 xxxxxx | 07961 xxxxxx |
| 0966 | Orange | 0966 xxxxxx | 07966 xxxxxx |
| 0973 | Orange | 0973 xxxxxx | 07973 xxxxxx |
| 0976 | Orange | 0976 xxxxxx | 07976 xxxxxx |
| 0979 7 | Jersey Telecom | 0979 7xxxxx | 07797 7xxxxx |
The following codes for pager numbers were also changed, so that all are in the 076xx range:
| Code | Operator | Before BNC | After BNC |
|---|---|---|---|
| 0399 → 01399 |
VodaPage | 0399 xxxxxx → 01399 xxxxxx |
076 99xx xxxx |
| 0399 0 → 01399 0 |
VodaPage | 0399 0xxxxx → 01399 0xxxxx |
Discontinued by 2001-04-28 |
| 0426 → 01426 |
BT Paging | 0426 xxxxxx → 01426 xxxxxx |
076 26xx xxxx |
| 0459 → 01459 |
VodaPage/PageOne | 0459 xxxxxx → 01459 xxxxxx |
076 59xx xxxx |
| 01523 | PageOne | 01523 xxxxxx | 076 23xx xxxx |
| 01893 | BT Paging | 01893 xxxxxx | 076 93xx xxxx |
| 0336 7 | Vodafone | 0336 7xxxxx | 076 637x xxxx |
| 0385 4 | Vodata? | 0385 4xxxxx | Unknown |
| 0385 6 | Vodata | 0385 6xxxxx | Unknown |
| 04325 | BT Paging | 04325 xxxxxx | 076 25xx xxxx |
| 04624 | Isle of Man? | 04624 xxxxxx | 076 24xx xxxx |
| 0660 | PageOne | 0660 xxxxxx | 076 61xx xxxx |
| 0839 | PageOne | 0839 xxxxxx | 076 61xx xxxx |
| 0881 | PageOne | 0881 xxxxxx | 076 81xx xxxx |
| 0941 | Orange (HPL) | 0941 xxxxxx | 076 41xx xxxx |
| 0941 1 | Orange (HPL) | 0941 1xxxxx | 076 411x xxxx |
Some of these codes, as indicated by the arrow "→", had already been changed during PhONEday to add a "1" after the initial zero, and now they have been changed again.
These fictional numbers are made available by Oftel for dramatic purposes, for example for quoting in TV, radio and film. Ofcom explains: "Telephone Numbers recommended for drama purposes cannot be allocated to Communications Providers for their customers because of the potential influx of calls that customers may receive should their Telephone Numbers be shown in a drama."[4]
| Number range type | Code area | Before PhONEday | Before BNC | After BNC | |||
|---|---|---|---|---|---|---|---|
| Code | Number range | Code | Number range | Code | Number range | ||
| Geographic | Leeds | 0113 | 496 0000 to 496 0009 | 0113 | 496 0000 to 496 0999 | ||
| Geographic | Sheffield | 0114 | 496 0000 to 496 0009 | 0114 | 496 0000 to 496 0999 | ||
| Geographic | Nottingham | 0115 | 496 0000 to 496 0009 | 0115 | 496 0000 to 496 0999 | ||
| Geographic | Leicester | 0116 | 496 0000 to 496 0009 | 0116 | 496 0000 to 496 0999 | ||
| Geographic | Bristol | 0117 | 496 0000 to 496 0009 | 0117 | 496 0000 to 496 0999 | ||
| Geographic | Reading | 0118 | 496 0000 to 496 0009 | 0118 | 496 0000 to 496 0999 | ||
| Geographic | Birmingham | 021 | 496 0000 to 496 0009 | 0121 | 496 0000 to 496 0009 | 0121 | 496 0000 to 496 0999 |
| Geographic | Edinburgh | 031 | 496 0000 to 496 0009 | 0131 | 496 0000 to 496 0009 | 0131 | 496 0000 to 496 0999 |
| Geographic | Glasgow | 041 | 496 0000 to 496 0009 | 0141 | 496 0000 to 496 0009 | 0141 | 496 0000 to 496 0999 |
| Geographic | Liverpool | 051 | 496 0000 to 496 0009 | 0151 | 496 0000 to 496 0009 | 0151 | 496 0000 to 496 0999 |
| Geographic | Manchester | 061 | 496 0000 to 496 0009 | 0161 | 496 0000 to 496 0009 | 0161 | 496 0000 to 496 0999 |
| Geographic | Tyneside/Durham/Wearside | 091 | 498 0000 to 498 0009 | 0191 | 498 0000 to 498 0009 | 0191 | 498 0000 to 498 0999 |
| Geographic | London | 01 | 946 0000 to 946 0009 | 0171 | 946 0000 to 946 0009 | 020 | 7946 0000 to 7946 0999 |
| Geographic | Northern Ireland | 028 | 9018 0000 to 9018 0999 | ||||
| Geographic | Cardiff | 029 | 2018 0000 to 2018 0999 | ||||
| Geographic | No area | 0632 | 960000 to 960009 | 01632 | 960000 to 960009 | 01632 | 960000 to 960999 |
| Mobile | n/a | 07700 | 900000 to 900009 | 07700 | 900000 to 900999 | ||
| UK-wide | n/a | 0306 | 999 0000 to 999 0999 | ||||
| Freephone | n/a | 0808 | 157 0980 to 157 0989 | 0808 | 157 0000 to 157 0999 | ||
| Premium rate services | n/a | 0909 | 879 0980 to 879 0989 | 0909 | 879 0000 to 879 0999 | ||
Although not directly connected with the official BigNumber changes, these number allocations were updated with the new prefixes and with additional areas, as well as changing from 10 to 1000 numbers allocated per block, around the same time as the other BigNumber changes occurred.[4][5]
Some widespread misunderstandings about area codes came about with the Big Number Change, most notably with London area codes. There is a widespread but erroneous assumption that London has two area codes 0207 and 0208, whereas in fact it has just one: 020. Similar misunderstandings came about with a few other area codes.