The scandal over the treatment of the journalists Birney and McCaffrey was compounded by an admission that the case had been brought by police in order to protect loyalists involved in the Loughinisland massacre.

Six Catholic men were shot dead in the County Down village after gunmen opened fire in a pub as their victims watched a World Cup football match in 1994. No one has ever been charged with the attack.

The journalists had been involved in a documentary titled ‘No Stone Unturned’, which exposed police failings and evident collusion. Their arrest earlier this year immediately appeared little more than a cover-up to prevent them from uncovering more uncomfortable truths. It was claimed the pair had been in receipt of ‘stolen information’ from a whistleblower linked to the office of the Police Ombudsman.

This week, the case was dropped and the journalists’ research materials retuned, but without any sign of apology or regret from those who directed the police actions.

They said: “Our first thoughts are with the Loughinisland families. The attack on us was an attack on them.”

During the hearing last week, lawyers for the men argued that the search operation was aimed at discovering sources and intimidating whistleblowers by a system more akin to a police state than a professed democracy. Justice Declan Morgan agreed the granting of the search warrants was “inappropriate” and the two journalists had acted in a perfectly proper manner to protect their sources.

“I think there was a malicious intent in this investigation,” said Mr Birney, adding: "I think it’s very well known that many in the upper ranks of the PSNI still have difficulty in the truth that there was collusion in Loughinisland and that the police did collude with the UVF in murdering six men in June 1994, almost 25 years ago.”

Mr Birney also called for the chief of the PSNI to apologise to the families of those killed in Loughinisland.