The security guidance comes in the aftermath of news that the phone records of Belfast-based journalist Barry McCaffrey were secretly searched by the PSNI during an investigation into allegations that a senior member of the force received payments from a private company.

Patrick Corrigan, Amnesty’s Northern Ireland programme director, said: “Following the revelations about PSNI accessing Barry McCaffrey’s phone records, we know that there are journalists in newsrooms across Northern Ireland deeply concerned that they may have been subject to police spying.

“That’s why we have published this guidance for journalists and human rights defenders, with practical advice on what they can do to find out if their phone records have been snooped on.

“Journalists play a crucial role in holding those in authority to account and have a long-established right to protect their sources.

“We are determined to get to the bottom of this police spying scandal, to discover how widespread this practice has been and to ensure it never happens again.”