Big Number Change

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 Saturday, April 22, 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.

1 Geographical number changes
2 Non Geographic Number Changes
3 Misunderstandings
4 See also
5 External links

Geographical number changes

The following changes took place in Great Britain:

Area Old Number New Number 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

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 68x 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 [1] is as follows:

Area Old number New number Actual county (if different)

County Antrim

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

County Armagh

Newry(5-digit) (01693) xxxxx (028) 302x xxxx Down Newry (6-digit) (01693) xxxxxx (028) 30xx xxxx Down Armagh(01861) xxxxxx (028) 37xx xxxx Portadown(01762) xxxxxx (028) 38xx xxxx Partially in Down

County 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

County Fermanagh

Enniskillen(01365) xxxxxx (028) 66xx xxxx Lisnaskea(013657) xxxxx (028) 677x xxxx Kesh(013656) xxxxx (028) 686x xxxx

County Londonderry

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

County Tyrone

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

Non Geographic Number Changes

The following changes where made to non geographic numbering ranges to bring them in the 08 Special Services range.

Code Charging Rate Old Number New Number 0345 Local Rate 0345 xxxxxx 0845 7xxxxxx 0645 Local Rate 0645 xxxxxx 0845 9xxxxxx 03745 National Rate 0374 5xxxxx 0870 4xxxxxx 0541 National Rate 0541 xxxxxx 0870 1xxxxxx 0990 National Rate 0990 xxxxxx 0870 5xxxxxx

Misunderstandings

Main article: UK telephone code misconceptions

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.