What does an unallocated phone number mean?
Ofcom hands out UK numbers in blocks and publishes the status of every block. A number from a block that no provider holds cannot belong to a real phone line.
The statuses in Ofcom's files
- Allocated: a provider holds the block and can give its numbers to customers.
- Free: available for allocation; no provider holds it.
- Protected and quarantined: not allocated to any provider.
- Reserved or designated: set aside, not allocated to a provider.
In the 07 mobile ranges alone, Ofcom lists 6,048 blocks: 5,525 allocated and 400 free, protected or quarantined (files of 2026-09-04).
What it means if a call or text shows one
If the number on your screen falls in a block no provider holds, the sender set a fake caller ID, or the number was copied wrongly. Either way, do not call it back and do not trust the message because of the number.
The reverse is not true: an allocated number can also be faked, and the provider shown is the original range holder, not necessarily today's network, because people keep their numbers when they switch.
Check any number with the UK number checker; it downloads Ofcom's file for the first three digits and does the matching on your device.
Sources
- Ofcom numbering data: Ofcom numbering data files S1, S3, S5, S7, S8, S9 (ofcom.org.uk, Download numbering data) as downloaded by Ofcom on 2026-09-04, copied unchanged from the Number::Phone data-files mirror, commit b842859. Ofcom: "We publish data on which UK telephone numbers are available for allocation or are allocated, and aim to update these files every Wednesday." — https://www.ofcom.org.uk/phones-and-broadband/phone-numbers/numbering-data; mirror: https://github.com/DrHyde/perl-modules-Number-Phone-data-files, read on 2026-09-29
Frequently asked questions
- Can an unallocated number send a text?
- Only with a faked sender. No provider holds the block, so no genuine phone line has that number.
- How often does Ofcom update the data?
- Ofcom says it aims to update the numbering files every Wednesday. The date of the files this site uses is shown on every result.
More guides
- Is this number a scam? A 6-point checklist
Six checks for an unknown UK number or text: the range, the number type, the cost of calling back, what it asks, the pressure, and how to verify.
- What is Report Fraud? The service that replaced Action Fraud
Since 4 December 2025 fraud and cyber crime in England, Wales and Northern Ireland is reported to Report Fraud, not Action Fraud. Where, how, and Scotland.
- Why do I keep getting loan texts, and how do I stop them?
The UK rules on marketing texts, what the ICO fined a loan-text firm for in 2026, and the steps that make the texts stop: don't reply, 7726, ICO.
- How to forward a scam text to 7726 (iPhone and Android)
Step by step for iPhone and Android, from the NCSC: what 7726 does with your report, what it costs, and what to do if 7726 does not work.
Last updated 2026-09-29. Independent information service. Number data from Ofcom shows the original range holder; numbers can be ported or spoofed. Not affiliated with Ofcom, the FCA, the ICO or any police service.