area codes (formerly known as dialling codes and STD codes prior to that) with associated areas are set out in Appendix A of the Ofcom document National Telephone Numbering Plan. Most geographic telephone numbers in the UK are 6 digits in length, with a 5 digit code. In the larger towns they are 7 digit with a 4 digit code and in the newer 02 areas they are 8 digit with a 3 digit code. There are still a few 5 digit numbers in existence in some code areas; Some of these have a 5 digit code, meaning the total number length is 10, rather than 11 digits, which some people find confusing nowadays. Others have a 6 digit code, meaning they are still 11 digits in total. There is still one area which has a 5 digit code and 4 digit numbers.
When people write down telephone numbers and when organisations display their numbers in literature and on their websites they will use a space or a dash to indicate the part of the number which is the code and the part which is the local number, or they may display the code in brackets. However, they often display their numbers incorrectly, or pause in the wrong place when speaking them, and not in accordance with Ofcome guidance. For example, people in London were used to quoting their number as a 7 digit number in the format 0171 XXX XXXX or 0181 XXX XXXX, but since the London codes changed to 020 a lot of people quote their number as 0207 XXX XXXX or 0208 XXX XXXX. This is incorrect as the digit after the 020 should be part of the number and not the code and the number should be quoted in two blocks of four – 020 7XXX XXXX or 020 8XXX XXXX. The Ofcom guidance is also quite confusing as it quotes these numbers as 2+8, meaning a 2 digit code and an 8 digit number. This is because they don’t count the initial 0, which is regarded as a network digit and not part of the area code. The 0 is also omitted when dialling in from outside of the UK.
When it comes to displaying UK numbers as international numbers the same principals should be used, except the international prefix +44 should be used instead of the leading 0 at the beginning of the code. Again many organisations incorrectly display their international number, either with the 0 included or the 0 included within brackets, such as +44 (0) 1XXX XXXXXX, when it should be +44 1XXX XXXXXX.
Below we show you the different types of UK geographic numbers and how they should be displayed, together with the Ofcom definition.
| Format Description | National Format | International Format | Ofcom Definition |
| 3 Digit Code with 8 Digit Number | 02X XXXX XXXX | +44 2X XXXX XXXX | 2+8 |
| 4 Digit Code with 7 Digit Number | 01XX XXX XXXX | +44 1XX XXX XXXX | 3+7 |
| 5 Digit Code with 6 Digit Number | 01XXX XXXXXX | +44 1XXX XXXXXX | 4+6 |
| 5 Digit Code with 5 Digit Number | 01XXX XXXXX | +44 1XXX XXXXX | 4+5 |
| 6 Digit Code with 5 Digit Number | 01XXXX XXXXX | +44 1XXXX XXXXX | 5+5 |
| *6 Digit Code with 4 Digit Number | 01XXXX XXXX | +44 1XXXX XXXX | 5+4 |
*Only applies to numbers starting with 2 and 3 in 0126977.
Here we provide you with both alphabetical and numerical lists of codes, including versions you can download and, unlike the official Ofcom list we make it much clearer what part of the whole number is the code and what is the local telephone number. We do this by only showing the digits in the code and not part of the number as well and by specifying the number of digits in the local numbers. The Ofcom list, for example, incorrectly shows the start of Northern Ireland numbers as part of the code. It also fails to show the code for 4 and 5 digit numbers in Brampton, Cumbria.
Click here for the alphabetical list of National Dialling Codes
Click here for the numerical list of dialling codes