The Prime Minister’s surveillance watchdog ordered police chiefs yesterday to reveal when snooping powers have been used to identify journalistic sources.

Interim Interception of Communications Commissioner Sir Paul Kennedy has launched an inquiry into potential misuse of the Regulation of Investigatory Powers Act following reports forces have used the legislation to access reporters’ telephone and email records.

He said he would undertake a full inquiry and make the findings public.

“I fully understand and share the concerns raised about the protection of journalistic sources so as to enable a free press,” said Sir Paul.

The commissioner acted after a slew of reports of police using the act, including in the Plebgate row and Chris Huhne speeding points scandal.