Interference from future mobile signals might make digital TV unwatchable for some Britons, Ofcom has said.

The telecoms watchdog is starting a research program to find out how to help people affected when future mobile technology is switched on.

About 3% of TV-watching Britons could suffer interference from fourth-generation (4G) mobile, said Ofcom.

Filters will solve the problem for some, said Ofcom, but others may have to use other ways to get TV signals.