London — 020 dialling code

About the 020 dialling code in London

020 is the geographic UK area code anchored on London, Greater London, listed in Ofcom’s National Telephone Numbering Plan. London has a population of approximately 8,982,000, and the dialling code reaches across the surrounding charging area rather than the town centre alone. When an inbound UK landline shows +44 20 on Caller-ID, the originating exchange is most likely physically located in or near London, with neighbouring exchanges on 023, 01997, 024.

Numbers in London’s 020 block were originally allocated to UK communications providers in 1,000-number sub-ranges (the legacy Ofcom block size for geographic codes), with newer allocations issued in 10,000-number blocks once the smaller blocks ran out. Each block is delegated to a Range Holder — typically Openreach (BT), Virgin Media O2, Sky, Gamma Telecom or one of a long tail of regional carriers — who is then responsible for assigning individual numbers to end-customers in the London charging area. The full table further down this page shows every currently-allocated range on 020 and the holder it was delegated to.

This is the same data Ofcom publishes every Wednesday in the public UK Numbering Data feed; we re-ingest the snapshot weekly, so the London allocations you see here are at most seven days old. Because UK numbers are portable, the current carrier of any specific 020 number in London can differ from the Range Holder shown — see Range Holder vs current provider for the explanation. To identify a specific caller, paste the full number into the lookup above: you’ll get the Range Holder, the allocation status, the London area-code metadata, and a live AI internet check summarising any public web reports about that exact number.

From abroad, a London 020 number is reached by dialling the international access prefix (00 from most of Europe, 011 from North America), then 44, then the local digits with the leading zero dropped. So a number written locally as 020 123 4567 becomes +44 20 123 4567 when dialled from outside the UK. Inbound calls to a London landline are charged at the recipient’s standard call-receive rate (free in most consumer tariffs), and outbound calls from a UK mobile or landline to a 020 number are billed at the caller’s own UK landline rate. Greater London consumers and businesses with a 020 CLI typically use Openreach copper or fibre, Virgin Media O2 cable, a Sky or TalkTalk retail bundle, or one of a long tail of regional or VoIP-based providers — the table further down this page shows the wholesale allocation that anchors each block, but the live retail carrier on a specific number can be different after porting.

If you have just received a missed call from a 020 number and you don’t recognise it, the most reliable next step is to paste the full number into the lookup above before calling back. The Ofcom Range Holder data tells you which wholesale carrier the block was issued to, which often gives away whether the call is a local resident, a national business renting a London-presenting CLI, or a VoIP service that could be operating from anywhere in the UK. The AI internet check then aggregates any public reports about the specific digits — Reddit threads, MoneySavingExpert forum posts, Trustpilot reviews, scam-reporting databases — so you have context before you decide whether to ring back.