UK regulators are teaming up with counterparts in the USA and Canada to crack down on 'spoof' calls from telemarketing schemes.
Spoofing is the term for when callers hide their identity behind a false or invalid phone number, which then appears on your phone when a call is made. (For help in dealing with cold calling, see our Stop Spam Texts & Calls guide.)
Telecoms watchdog Ofcom says the tactic is often used by organisations carrying out unsolicited, misleading and sometimes fraudulent telemarketing activities, which can catch consumers out.
The spoof numbers, which can be a series of random digits or an unrelated real number, prevent consumers from returning the call to find out who is contacting them or opting out of future marketing calls.
Additionally, the practice makes it harder for regulators to trace the firms responsible.
Now Ofcom and the UK's Information Commissioner's Office are joining forces with regulators from the USA and Canada to share resources and intelligence to solve the growing spoofing problem.
Ofcom consumer group director Claudio Pollack says: "International co-operation is vital in finding effective remedies to the problem of number spoofing.
"We are thoroughly committed to this joint effort and are determined to put a stop to this harmful practice and take action against those responsible."