Greater London UK dialling codes

How Greater London dialling codes are organised

The UK numbering plan splits geographic codes into 01 (most of the country) and 02 (the largest metros — London 020, Cardiff 029, Belfast 028, Coventry/Northampton 024, Southampton/Portsmouth 023 and Tyneside 0191 sit alongside the 02-series equivalents). The 4 codes listed above for Greater London all sit inside this geographic block, which means a call to any of them is charged at the caller’s standard local rate (typically included in inclusive call allowances on mobile and landline tariffs). None of these prefixes are revenue-share or premium-rate — those live in the 084x, 087x, 09x and 118x ranges and are listed on our non-geographic prefixes index.

Each town hub on the cards above is fed directly from Ofcom’s published Numbering Data, which lists every 10,000-number block (NDC + four-digit prefix) and the Communications Provider that currently holds the allocation. Following a town link takes you to a page that breaks down every range assigned within that code, the Range Holder behind each block, the allocation status (assigned, reserved, free, withdrawn or returned) and a search form you can drop any full ten-digit number into for a real-time reverse lookup. If the holder has spawned spam-call complaints, the AI internet check at the top of the lookup result will surface that context from public scam-tracking sites and recent news mentions.

Region groupings on this hub follow Ofcom’s own administrative labels rather than ceremonial-county or postal-region boundaries, which is why a town like Slough (01753) sits under Berkshire on this site even though postally it shares an SL postcode with parts of Buckinghamshire. We refresh the underlying allocations weekly from the official feed, and the rendered HTML you’re reading is cached and served from the edge, so every hub here is at most seven days out of date even when Ofcom publishes between our regular refreshes.