Looking up a UK number works best in layers, from the information that is always available to the information that only sometimes exists. Our view is that most people skip the first layer and go straight to paid "reverse lookup" sites, when the free layers answer the real question - is this call safe - far more reliably.
Step 1: write the number in the standard format
UK numbers can appear as 07700 900123, +44 7700 900123 or 0044 7700 900123. They are the same number. Lookups work best with the national format starting with 0, so drop the +44 and add a 0 in front. Most UK numbers have 11 digits including that 0; a few older landline areas have 10.
Step 2: read what the prefix tells you
| Starts with | Type |
|---|---|
| 01, 02 | Landline linked to an area |
| 03 | Non-geographic, charged like a landline |
| 07 (except 070 and 076) | Mobile |
| 080 | Freephone |
| 084, 087, 09 | Service numbers with extra charges |
The dialling codes page lists area codes such as 0161 Manchester or 01204 Bolton, and explains numbers like 0333 and 0800.
Step 3: check reports and allocation data
On Who Rang, each number page collects reports from people who received calls from it, together with details from Ofcom's numbering data: the type of number, the provider the number block was allocated to and when. That last part is more useful than it sounds. If a number sits in a range that was never allocated to any provider, the caller ID was almost certainly faked. Keep in mind that numbers can move networks, so the original provider isn't always the current one.
Step 4: search it in quotes
Put the number in quotation marks in Google, once with spaces and once without. Genuine businesses publish their numbers on contact pages, so a match on a bank's or courier's website is a good sign. Remember that scammers copy real numbers, so a match isn't proof that the call came from that business.
What a lookup can't do
No legitimate UK lookup reveals the private owner of a mobile number. Landlines listed in the phone book can be found through directory enquiries, but ex-directory numbers can't. If a site asks for payment to "unlock" a name, it is selling you hope rather than data.
If the number turns out to be a scam, forward it to 7726 and add your own report so the next person sees it. You can start by browsing the catalogue of numbers people have already checked.