List of dialling codes in the United Kingdom

The national telephone numbering plan is maintained by Ofcom, an independent regulator and competition authority for the UK communications industries.

When dialling within the country, all area codes are preceded by the national trunk prefix 0, which has been included in all listings in this article.

0 was traditionally the number dialled for the operator for long-distance calls before subscriber trunk dialling (STD) was introduced, and so was retained as a prefix for direct-dialled calls.

When calling from a mobile telephone or through a VoIP service, such as BT's 'Digital Voice', the area code is always needed.

Unlike the Crown Dependencies of Jersey, Guernsey and the Isle of Man which use the UK area codes 01534, 01481 and 01624, respectively, telephone numbers in British Overseas Territories do not come under the UK telephone numbering plan.