The journalists, Trevor Birney and Barry McCaffrey, were arrested in 2018 in connection to their work investigating the 1994 Loughinisland massacre.

The pair filed a complaint with the IPT after Northern Ireland’s Court of Appeal ruled in 2020 that the search warrants and arrests were unlawful.

Last year, it emerged that the tribunal had discovered the PSNI had previously accessed Mr McCaffrey’s phone while he was investigating potential corruption in the force. Further disclosures by the police to the tribunal have revealed further incidents of police surveillance.

Last week, lawyers acting for the BBC also wrote to the IPT about the alleged police surveillance of one of its former journalists, Vincent Kearney, following disclosures to the tribunal earlier this year.

​The two journalists are being supported by the National Union of Journalists (NUJ), Amnesty International UK and the Committee on the Administration of Justice.

Patrick Corrigan, Amnesty’s Northern Ireland director, said: “What is emerging, piece by piece, is a hugely disturbing picture of covert and repeated surveillance of journalists by the police.

​”This tribunal has now become a crucial test case for press freedom in the UK.”