Who called me from a Callmonitor Limited number?

Callmonitor Limited is a UK communications provider. That means Ofcom has allocated Callmonitor Limited one or more blocks of UK telephone numbers under the National Telephone Numbering Plan, which Callmonitor Limited can either use for its own customers or sub-allocate to resellers and downstream providers. In total, Callmonitor Limited currently holds 5 allocated number blocks in our copy of the Ofcom plan.

Callmonitor Limited's number ranges are concentrated in (020) (London), 0800, 0845, 0870. Across all of its allocations the split is roughly 3 premium-rate, 1 freephone, 1 geographic landline blocks. You can use the tables below to jump straight to a specific Callmonitor Limited area code or number block and see the common call patterns reported for it.

The oldest Callmonitor Limited number block in the Ofcom data was allocated in 2004. Allocation dates matter because a number that has been live for many years is more likely to be a settled business or residential line, whereas a very recently-allocated block is more commonly seen in VoIP and virtual-number services — the kind sometimes used for short-lived marketing or scam campaigns.

Is a Callmonitor Limited number safe to answer? In most cases, yes — the overwhelming majority of calls from any UK provider's range are ordinary, legitimate calls. However, two things are important to understand. First, because Callmonitor Limited can sub-allocate or resell its numbers, the fact that a number sits in a Callmonitor Limited block does not mean Callmonitor Limited itself is calling you. Second, UK caller IDs can be spoofed: scammers can make a call appear to come from a Callmonitor Limited number they don't control. So treat the number as a clue, not proof — judge the call on what the caller actually asks for.

If a Callmonitor Limited number called you and you're unsure, don't share security details, bank information or one-time passcodes, and don't return the call until you've verified it independently. You can block the specific number on any UK smartphone from the recent-calls list, enable free network-level call screening through your own landline provider, and register with the Telephone Preference Service (TPS) to cut legitimate marketing calls. Persistent nuisance calls can be reported to Ofcom, and suspected scams to Action Fraud (or Police Scotland on 101).