Surveillance 'This involves some of the biggest state organisations'

After a tribunal ruled that the investigative journalists, Trevor Birney and Barry McCaffrey, were unlawfully spied on to find out their sources, the pair were at pains to stress that they considered what was uncovered to be just the tip of the iceberg.

- Haroon Siddique

They believe the case highlights an endemic problem in the relationship between police and journalists across the UK, stretching far beyond Northern Ireland where they are based.

Their 2017 film No Stone Unturned, about apparent collusion between the police and suspected murderers in the 1994 Loughinisland massacre, led to the case at the investigative powers tribunal (IPT).

But this was not solely about the legacy of the Troubles.

The pair's 2018 arrest over the alleged leaking of two documents in the documentary, for which the Police Service of Northern Ireland (PSNI) paid them and the production company damages of £875,000, came 20 years after the signing of the Good Friday agreement.

Furthermore, the tribunal found that McCaffrey had been targeted for an altogether different story.