UK Telephone Numbers and Codes

UK Telephone Numbers and area codes

The telephone service in the United Kingdom was originally provided by private companies and local councils. But by 1913 nearly all of them had been taken over by the Post Office. Post Office Telecommunications was reorganised in the 1980s as British Telecommunications (British Telecom, or BT).

Subscriber Trunk Dialling (STD) was introduced in 1958 and this allowed a caller to bypass the local exchange operator and call another telephone directly. Uniform exchange codes were allocated for every exchange in the country as STD was rolled out. These exchange codes were originally based on two letters of the place name of the exchange, the letters becoming numbers according to their allocation on the telephone dial ('O', however, became a zero). For example Aylesbury was given the STD code 0296, where the letter A can be found on the number 2 of the dial and the letter Y on the number 9. Many current Telephone Area Codes still contain these original 2 numbers.

Telephone numbers in the UK public network usually consist of 10, or occasionally 9, digits. The number is prefixed with a 0 when dialled from within the UK or with "+44" when dialled from abroad. The first few digits define the type of number - see this list of prefixes. There are several exceptions to this format including Helplines and Directory Enquiries numbers.

Some definitions: