The PSNI has been ordered to hand over previously withheld material about the McGurk’s Bar Massacre after a four-year legal battle.
Fifteen people were killed when the UVF detonated a bomb at the north Belfast bar in December 1971.
At the time security forces blamed the IRA for the North Queen Street blast but this was later shown not to be true.
Campaigners believe there was collusion in the murders and that attempts were subsequently made to mislead the public.
Campaigners say the Information Rights Tribunal has now ordered PSNI chief constable Jon Boutcher to disclose the blocked information.
Ciaran MacAirt, from the research charity Paper Trail, has carried out groundbreaking research into the attack.
In December 2020 Mr MacAirt, whose grandmother Kitty Irvine, was killed in the explosion, requested information under the Freedom of Information Act about “the provenance and source of police” information provided to a Joint Security Committee meeting which took place after the attack.
Those present at the 1971 meeting included then Chief Constable, Graham Shillington and the head of Special Branch.
They presented an assessment to Stormont Prime Minister Brian Faulkner, the General Officer Commanding the British Army Harry Tuzo, and minister John Taylor, also known as Lord Kilclooney.
Mr Taylor recently came in for criticism after appearing to question the innocence of those killed.
The police briefing included the false claim that “circumstantial evidence indicates that this was a premature detonation and two of those killed were known IRA members at least one of whom had been associated with bombing activities.
“Intelligence indicates that the bomb was destined for use elsewhere in the city,” the briefing added.
Mr MacAirt later traced the “disinformation” to what he describes as a “secret agreement” between Brigadier Frank Kitson and the RUC, reached within hours of the explosion.
The British army’s Belfast commander, Frank Kitson, who died last year, is believed to have set up the shadowy Military Reaction Force (MRF), which is linked to the murder of several Catholic civilians in the early years of the Troubles.
An entry in the Commander’s Diary for 39 Brigade found by Mr MacAirt shows that Mr Kitson told his staff four hours after the bomb blast that the “RUC have a line that the bomb in the pub was a bomb designed to be used elsewhere, left in the pub to be picked up by the Provisional IRA.
“Bomb went off and was a mistake,” it states.
“RUC press office have a line on it – NI should deal with them.”
The PSNI later refused a request “for the provenance and source of this false intelligence”.
The tribunal has now told police to hand over the requested information.
Mr MacAirt was critical of the PSNI.
“This important win also proves that PSNI not only withheld significant information from the historic investigations, courts and families, but also continues to withhold critical evidence in the mass murder of our loved ones,” he said.
Christopher Stanley, of KRW Law, said: “The Chief Constable has demonstrated sense and courage previously on legacy issues.
“He should read this judgment and reflect upon it.”
The PSNI was contacted.
