Mobile numbers within the UK are normally displayed as a 5 Digit code and a 6 digit number, e.g. 07XXX XXXXXX. However, other non geographic numbers are usually displayed as a 4 digit code and 7 digit number, e.g. 03XXX XXXXXX or 08XXX XXXXXX. However, some older 0800 numbers only have 6 digits after the code and so are displayed as 08XX XXXXXX.
UK mobile numbers are normally accessible internationally, but not all service number types listed below are and this varies depending which country you are calling from. To display a UK mobile number internationally you would use the format +44 07XXX XXXXXX.
The first two or three digits in a UK telephone number will tell you what type of number it is and give you an idea of the associated charges when calling such a number. The number ranges and descriptions are as follows:
| Code Range | Description |
| 00 | International dialling codes. |
| 01 | Geographic numbers. Included in free call allowances. |
| 02 | Expanded geographic numbers. Included in free call allowances. |
| 030 | Numbers used by public sector bodies and non-profit organisations charged at geographic rates and included in free call allowances. |
| 033 | Numbers used by other companies and organisations charged at geographic rates and included in free call allowances. |
| 034 | Numbers migrated from 084 numbers, which were charged at a special rate. Now charged at geographic rates and included in free call allowances. |
| 037 | Numbers migrated from 087 numbers which were charged at a special rate. Now charged at geographic rates and included in free call allowances. |
| 055 | Corporate numbers. |
| 056 | Location independent electronic communications. |
| 070 | Personal numbers which individuals can route to their current destination. Previously charged at a higher rate but now charged at mobile rates and included in free call allowances. |
| 071 | Mobile telephone numbers. Included in free call allowances. |
| 072 | Mobile telephone numbers. Included in free call allowances. |
| 073 | Mobile telephone numbers. Included in free call allowances. |
| 074 | Mobile telephone numbers. Included in free call allowances. |
| 075 | Mobile telephone numbers. Included in free call allowances. |
| *076 | Radio paging services. |
| 077 | Mobile telephone numbers. Included in free call allowances. |
| 078 | Mobile telephone numbers. Included in free call allowances. |
| 079 | Mobile telephone numbers. Included in free call allowances. |
| 080 | Freephone numbers. |
| 082 | Internet for schools. |
| 084 | Low rate chargeable numbers which are not normally included in free call allowances. |
| 087 | Higher rate chargeable numbers which are not normally included within free call allowances. |
| **090 | Premium rate services. |
| 091 | Premium rate services. |
| 098 | Premium rate services with sexual content. |
*07624 is used for mobile telephone numbers and radio paging services within the Isle Of Mann, but no new numbers are being allocated within this range.
**0908 and 0909 are being used for sexual entertainment services, but no new numbers are being allocated within these ranges.
From Ofcom’s Telecoms Numbering page you can Download numbering data – Ofcom a full list of mobile phone and special number providers and you can also search for the provider associated with a particular number range on https://www.telecom-tariffs.co.uk/. Note that, particularly with regard to special numbers, providers don’t always own everything after the first 5 digits and ownership can be split down as far as a 100 number range. Also note that these are the number ranges originally allocated to providers but it does not mean that a subscriber to a given telephone number is using that provider since they may have ported their number to another provider.