The different 03 numbers
Ofcom introduced 03 numbers as an alternative to chargeable 08 numbers such as 0870, so that an organisation can have a single national number without callers paying extra. The Numbering Plan splits them into four groups:
| Starts with | Who may use it |
|---|---|
| 030 | Only public sector bodies and not-for-profit bodies |
| 033 | Anyone: the Numbering Plan sets no restriction |
| 034 | Organisations moving from the matching 084 number, for example 0845 to 0345 |
| 037 | Organisations moving from the matching 087 number |
Ofcom notes that many public sector bodies have moved from 0845 numbers to 0345.
What they cost to call
- A call to an 03 number costs no more than a national rate call to an 01 or 02 number, and must count towards inclusive minutes in the same way, from any line: mobile, landline or payphone.
- Outside allowances, Ofcom’s guide puts landline calls at up to 16p a minute, with a set-up fee of about 23p at many providers, and mobile calls at 3p to 65p a minute.
- The organisation you call is not allowed to take a share of what you pay for the call.
Who holds 0333 and 0345 numbers
Ofcom allocates 03 numbers to phone companies in blocks, and those companies give individual numbers to their customers. In the files of 11 November 2026:
- 3,453 blocks of 03 numbers are allocated, to 271 phone companies.
- 234 blocks of 0333 numbers are allocated, to 134 companies; the largest holders are Gamma Telecom Holdings Limited, Colt Technology Services, GCI Network Solutions Limited.
- 738 blocks of 0345 numbers are allocated, to 96 companies; the largest holders are Vodafone Ltd (C&W), BT, PLATFORMX COMMUNICATIONS LIMITED.
The phone company is not the organisation that called you. Ofcom holds no information on who uses individual numbers within a block.
A call from an 03 number
An 03 number on your screen can be a public body, a business, a sales call, or a faked caller ID: the number alone cannot tell you which. If the caller says they are from an organisation, hang up and call it back on a number from its official website. For sales calls you never agreed to, the Telephone Preference Service (itself on 0345 070 0707) is free to join.