141 is a privacy setting for one call, not a way to make a call anonymous. It tells the network not to show your number to the person you're ringing. Everything else about the call - who made it, when and to whom - is still recorded by the networks involved.
Who can see a 141 number
| Who | Can they see or trace it? |
|---|---|
| The person you call | No - they see "withheld", "private" or "no caller ID" |
| Their 1471 service | No - it says the caller withheld their number |
| Apps that claim to unmask withheld numbers | Not reliably for UK network calls; be sceptical |
| The phone networks | Yes - the number is passed between networks for billing and regulation |
| The police | Yes, through lawful requests to the networks |
| Emergency services (999) | Yes - withheld numbers are still shown to emergency services |
If you're receiving withheld nuisance calls
You can't trace the caller yourself, but you can start the process:
- Keep a log of every call: date, time and what was said.
- Call your phone provider on the number on your bill and ask about their nuisance or malicious calls service. Providers can investigate calls made to your line, including withheld ones.
- If the calls are threatening, abusive or persistent, report them to the police on 101, or 999 if you're in danger.
- Meanwhile, reject withheld calls: BT landline customers can do this with Call Protect (1572), and many providers offer anonymous call rejection.
If you're using 141 yourself
Using 141 is legal and common - doctors, social workers and people protecting their privacy use it every day. Someone leaving an abusive relationship, for example, may withhold their number for good reason, which is exactly why the recipient can't simply reveal it. It just isn't a cloak for harassment. Persistently using a phone network to cause someone annoyance or anxiety can be an offence under the Communications Act 2003, whatever appears on their screen.
For whether you can find out the number behind a withheld call without the police, see can I find out a withheld number. Whether 141 still works on today's phones is covered in does 141 still work for withheld.