Calls from (020) 3935 XXXX — London
Block (020) 3935 XXXX is allocated by Ofcom to BT, on the London exchange (allocated 2017).
(020) 3935 XXXX is a number block in London, an area with a population of approximately 9,540,000. Standard landlines in this area use the format 020 3935 1234, with the first part being the dialling code and the rest being the local number.
This block — (020) 3935 XXXX — was allocated by Ofcom to BT in 2017. BT either operates the numbers directly or sub-allocates them to resellers and downstream carriers, which is why a single (020) 3935 XXXX prefix can be used by many different organisations. You can verify any allocation against Ofcom's National Telephone Numbering Plan, which is updated weekly.
Insurance and accident-claims cold calls remain a heavy source of unsolicited (020) 3935 XXXX-prefix traffic. Since 2019 it has been illegal under UK law to make unsolicited cold calls about pensions, and similar tightening is in force for insurance leads. You can register your number with the TPS for free to block legitimate UK marketing calls.
If a (020) 3935 XXXX number called you and you're not sure who it was, the safest steps are: don't return the call until you've verified it (search the full number online first), don't share personal or financial details, and register the number with the Telephone Preference Service (TPS) if it's a marketing call. Persistent unwanted calls can be reported to Ofcom and the ICO. To block a specific number on most UK mobiles and landlines, you can also enable network-level call screening through your provider.
FAQs about (020) 3935 XXXX
Is (020) 3935 XXXX a real UK phone number?
Yes. (020) 3935 XXXX is part of an Ofcom-allocated UK number block — any number starting with that prefix is a real, dialable UK number assigned by Ofcom to BT for use on the UK public telephone network.
Who owns the (020) 3935 XXXX number block?
(020) 3935 XXXX is currently allocated to BT in Ofcom's National Telephone Numbering Plan. The allocated carrier may operate the numbers directly or sub-allocate them to downstream resellers — both arrangements are normal under UK telecoms rules.
Where is a (020) 3935 XXXX number based?
(020) 3935 XXXX is associated with London. UK geographic numbers historically indicated the location of the line, although VoIP services and number-portability rules mean a (020) 3935 XXXX number can technically be used anywhere a CP routes it. For most UK landlines the geographic match still holds.
How do I block calls from (020) 3935 XXXX?
On most UK smartphones, open the recent-calls list, tap the number, and choose 'Block this caller'. UK landlines from BT, Sky, TalkTalk and Virgin Media include free 'BT Call Protect'-style screening you can enable in your provider's app. You can also register your number with the Telephone Preference Service (TPS) at tpsonline.org.uk to opt out of legitimate UK marketing calls.
Other blocks in (020)
Try a different block within the same UK area code:
