Criminals using internet-based calling technology to make it look like a phone call or text is coming from a real telephone number will soon be blocked if not from UK.

Ofcom said it expected the implementation to be introduced at pace as a “priority”.

After months of discussions the major networks have agreed, but so far only one has put measures in place.

“We’ve been working with telecoms companies to implement technical solutions, including blocking at source, suspicious international calls that are masked by a UK number,” said Lindsey Fussell, Ofcom’s networks and communications group director.

She added tackling the phone scams issue was a “complex problem” that required a coordinated effort from the police, government, other regulators and industry.

The services that use this internet data calling also known as Voice Over Internet Protcol (VoIP) include WhatsApp, Skype, Zoom and Microsoft Teams.

Gabriel Cirlig, of US cyber-security company Human, said telecoms companies were not inspecting the traffic they received from VoIP providers, they just let it through on to the network.

“Because of this lower barrier of entry, it is very easy for scammers to build their own systems to spoof mobile numbers – even pretending to be legitimate corporate telephone networks in order to have access to legitimate telco infrastructure.”

Matthew Gribben, a former consultant to GCHQ, the UK Intelligence and Security Agency, agrees. Has seen many scams while monitoring networks.

“It’s the foreign VoIP providers that are enabling these gangs to operate, so it will make a huge dent in this,” he said. “It doesn’t fix everything but it’s an excellent step in the right direction.”

US authorities have ordered mobile operators to implement the new protocols nicknamed “Stir and Shaken” (after the Fictional 007 Spy) by the end of 2021.

Ofcom told the BBC, introducing full authentication in the UK would only be possible when the technology when it is upgraded and due to be completed by 2025.

Let’s hope this will also stop cloned numbers