Who Called Me from 01883 (Caterham)?

01883 is the UK dialling code for Caterham, in the historic county of Surrey, covering an area with a population of approximately 33,000. Numbers in this area follow the format 018831234567 — the dialling code, followed by a local number assigned to a specific Communications Provider (CP).

Ofcom has allocated 163 number blocks within the 01883 range, spread across BT, Virgin Media, Sky, TalkTalk, Gamma and many smaller UK CPs. Each block of 1,000 (or sometimes 10,000) numbers is owned by a single CP, which may then assign individual numbers to its own customers or to resellers further down the chain. You can see the full block-by-block allocation list below.

Although 01883 originally indicated the geographic location of the line, UK number portability means a phone with this prefix can technically be located anywhere. For most landlines the geographic match still holds, but for VoIP-only numbers it does not. If you receive a call from a 01883 number and you don't recognise it, you can match the next four digits (the "block") against the table below to identify the originally-allocated network operator.