How caller ID spoofing works

Updated 2026-05-02

Caller ID is not a security feature. The number on your screen is set by the originating network and can be changed at will using legitimate VoIP services. Scammers exploit this by displaying real bank, HMRC, or police numbers to gain trust.

Why spoofing exists

Spoofing has legitimate uses — call centres displaying a single 'callback' number, doctors hiding personal mobiles, businesses showing branded numbers. The same mechanism is abused for fraud.

What Ofcom is doing

Since 2024, UK networks must block international calls with spoofed UK numbers and verify that the displayed number belongs to the calling party where possible. STIR/SHAKEN-style verification is rolling out gradually.

How to defend yourself

Treat caller ID as a hint, not proof. For anything important — bank, HMRC, police — hang up and call back on a verified official number from a different phone if possible.

Frequently asked questions

Can scammers spoof my own number?

Yes — 'neighbour spoofing' uses numbers similar to yours. Receiving a call from your own number means it's spoofed; you didn't call yourself.