UK phone companies will make it harder for scammers to use their networks, under a range of measures proposed by Ofcom.
Almost 45 million people were targeted by scam calls and texts last summer with nearly one million who followed the scammers’ instructions, risking financial loss and emotional distress.
But Ofcom is proposing strengthened rules and guidance to combat number "spoofing".
Spoofed numbers include calls originating from abroad that do not have a valid caller ID, using a number that does not meet the UK's 10 or 11-digit format, and calls appearing to be from numbers that are already on Ofcom's Do Not Originate list.
The regulator says all telephone networks involved in transmitting calls will be expected to block numbers that are clearly "spoofed" to better protect millions of people.
Ofcom is also proposing new guidance to help companies prevent scammers from accessing valid phone numbers.
The regulator allocates millions of telephone numbers, usually in large blocks, to telecoms companies.
These companies can then transfer the numbers to other businesses or individuals. All phone companies are expected to take reasonable steps to stop their numbers being misused, but these efforts can vary.
Its new guide sets out clear expectations for phone companies to make sure they run "know your customer" checks on business customers and that companies should also act to prevent any further potential misuse.
Scammers’ tactics are constantly evolving and becoming more sophisticated, so there is no single solution that will stamp out scam calls. But Ofcom is also examining how technology can help prevent scam calls at source in the future.
For calls originating in the UK, this would involve the network from which the call is being made "authenticating" the caller’s ID information before connecting them.
Jonathan Rose, Ofcom’s director for Northern Ireland, said: "The threat posed by scammers has grown significantly in recent years, and the sophisticated tactics used by these criminals can have devastating consequences for victims.
"We’re taking action so phone companies have stronger systems in place to disrupt scams.
"While there is no silver bullet that will end the scourge of scam calls completely, we’re working with industry on how we can use technology to make it as difficult as possible to reach people."
