Who called me from a Red Matter Limited number?

Red Matter Limited is a UK communications provider. That means Ofcom has allocated Red Matter Limited one or more blocks of UK telephone numbers under the National Telephone Numbering Plan, which Red Matter Limited can either use for its own customers or sub-allocate to resellers and downstream providers. In total, Red Matter Limited currently holds 8 allocated number blocks in our copy of the Ofcom plan.

Red Matter Limited's number ranges are concentrated in (023) (Southampton & Portsmouth), 0115 (Nottingham), 01473 (Ipswich), 01883 (Caterham). Across all of its allocations the split is roughly 6 geographic landline, 1 03 non-geographic, 1 premium-rate blocks. You can use the tables below to jump straight to a specific Red Matter Limited area code or number block and see the common call patterns reported for it.

The oldest Red Matter Limited number block in the Ofcom data was allocated in 2010, and the most recent in 2012. 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 Red Matter 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 Red Matter Limited can sub-allocate or resell its numbers, the fact that a number sits in a Red Matter Limited block does not mean Red Matter Limited itself is calling you. Second, UK caller IDs can be spoofed: scammers can make a call appear to come from a Red Matter 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 Red Matter 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).