Calls from 0000000000: what an all-zeros number means

Your phone rings and the screen shows +000000000, or simply a row of zeros. There is no name and nothing sensible to call back. If you searched those zeros to find out who it was, you are in large company.

What does it mean when all zeros call you?

Every call carries caller ID, a small piece of data set by the system that places the call. A business switchboard or an internet calling service can fill that field with almost anything, including a string of zeros. When you see zeros, the caller's system has sent a number that cannot be dialled.

Sometimes that is down to a badly configured phone system. It is also a very easy way to make sure you cannot see, block or ring back the real number. No working UK phone number is made up only of zeros, so there is no owner to trace, and the screen gives you no way to tell a clumsy company from a scammer. The sensible approach is to treat the call as unknown and judge it by what the caller says.

Why does 00000 keep calling me?

+000000000 is the most looked-up number on UnwantedNumbers. It was searched 1,273 times in the past 30 days, far more than any other number on the site, yet its page has only a single comment. People get the call, search for it and come away none the wiser, because the zeros do not point to anyone.

Repeat calls from zeros may not come from the same caller at all. Any number of operations can send the same blank-looking ID, so two calls a week apart could be entirely unrelated. What you can judge is the call itself. A recorded warning, an urgent demand for payment or a silence followed by a click are all reasons to hang up.

Shouldn't my network block these calls?

Ofcom has tried to make that happen. Under General Condition C6.6, amended in November 2022, phone providers must block calls carrying caller ID that is invalid or cannot be dialled, where this is technically feasible. Emergency calls are exempt. Ofcom does not tell providers which method to use, so approaches differ between networks and some of these calls still get through.

Two newer measures target fake British numbers used from abroad. Since 29 January 2025, overseas calls pretending to come from a British landline have had to be stopped by UK networks. Ofcom's July 2026 guidance extends this to mobiles: a call from abroad presenting a +447 number now reaches you with its caller ID hidden, unless that number can be verified. Callers who used to borrow British-looking numbers now find it harder, though withheld numbers and rows of zeros still turn up.

How number spoofing works in the UK

Spoofing means making a call display a number that is not really the caller's. It is cheap and needs no special equipment. A spoofed call might show a bank's genuine phone number, a local-looking 01 or 02 number, or nothing useful at all.

Take 02077230741, a London number where users report a recorded voice warning that their credit card has been compromised. Whoever is behind those calls may have no connection to the person or business the number is registered to. This is why the number on your screen should never be your only reason to trust a call.

If someone says they are from your bank, HMRC or your broadband provider, end the call and ring the organisation on a number you have found yourself, from a card, a bill or its official website. A scammer can fake the number they call from, but a call you place to the genuine number goes to the genuine organisation. On a landline, wait a few minutes or use a different phone, so you know the line has cleared.

My number has been spoofed. What can I do?

Sometimes it works the other way round: strangers ring you to ask why you called them, when you did not. That usually means someone has used your number as their fake caller ID. It does not mean your phone has been hacked, and you are not responsible for the calls.

• Tell people who ring back, calmly, that the call did not come from you and that your number is being misused.
• Contact your network provider and explain what is happening. Keep a note of the dates and the numbers that rang you back, as this gives them something to investigate.
• Think about changing your voicemail greeting for a while to say your number is being spoofed. It saves you repeating the explanation.
• If a caller tells you they lost money after a call that showed your number, point them to Report Fraud.

Spoofers tend to cycle through numbers quickly, so in many cases the call-backs tail off on their own.

I answered a call from zeros. What now?

• If it was silent or a recording and you hung up, you do not need to do anything more.
• If you pressed a key, gave your name or confirmed your address, expect further contact. Be wary of texts or emails that use those details to sound genuine.
• If you gave card or bank details, or paid anything, call your bank using 159 or the number on your card. Then tell Report Fraud, either online through reportfraud.police.uk or by phoning 0300 123 2040; people in Scotland should call Police Scotland on 101 instead.

Because the zeros cannot be blocked like a normal number on every handset, it is often easier to filter by type. On an iPhone, Settings has a Silence Unknown Callers switch for the Phone app, which sends anyone not in your contacts to voicemail without ringing. On most Android phones, the Phone app's settings include a blocked numbers page where you can switch on blocking for unknown or private callers.

For any other number that rings you, a quick search on UnwantedNumbers shows what others have experienced. If you are in the US and getting spoofed calls, you can report them to the Federal Trade Commission at reportfraud.ftc.gov. Signing up to the FTC's National Do Not Call Registry (donotcall.gov) will not stop scammers, though it does keep law-abiding telemarketers away.