Northern Ireland's police force unlawfully placed two investigative journalists under surveillance to try and find out their source, a London tribunal ruled on Tuesday.

A London tribunal ruled that Northern Ireland's police unlawfully surveilled journalists Trevor Birney and Barry McCaffrey to uncover their source for a documentary. The film 'No Stone Unturned' alleged police involvement in the 1994 Loughinisland massacre.

For this court to have found that a Chief Constable has acted unlawfully, we think is a major embarrassment, and it’s something that needs there to be a public inquiry."

It found that the actions of police when mounting an undercover surveillance operation were disproportionate and undermined the domestic and international protections available for the media. The PSNI has been ordered to pay £4,

The Police Service of Northern Ireland (PSNI) and Metropolitan Police acted illegally by spying on two Belfast journalists' to identify their sources. The landmark ruling was made by the Investigatory Powers Tribunal (IPT) in a case brought by Barry McCaffrey and Trevor Birney.

A covert surveillance operation authorised by a Northern Ireland police chief in a bid to unmask a journalistic source was unlawful, a tribunal has ruled.