On 4 December 1971 , the loyalist Ulster Volunteer Force ( UVF ) detonated a time bomb at the door of McGurk 's public house in Belfast . The pub was frequented by Irish Catholics/nationalists . The explosion caused the building to collapse , killing fifteen Catholic civilians and wounding seventeen more . It was the deadliest attack in Belfast during the Troubles . The book '' Killing For Britain '' ( 2009 ) , written by former UVF member ' John Black ' , claims that the MRF organised the bombing and helped the bombers get in and out of the area . Two days before the bombing , republican prisoners had escaped from nearby Crumlin Road Prison . Security was tightened , and there were many checkpoints in the area at the time . However , locals claimed that the security forces helped the bombers by removing the checkpoints an hour before the attack . One of the bombers — Robert Campbell — said that their original target had been The Gem , a nearby pub that was allegedly linked to the Official IRA . It is claimed the MRF plan was to help the UVF bomb The Gem , and then blame the bombing on the Provisional IRA . This would start a feud between the two IRA factions , diverting them from their fight against the security forces and draining their support . Campbell said that The Gem had security outside and , after waiting for almost an hour , they decided to bomb the nearest ' Catholic pub ' instead . Immediately afterward , the security forces claimed that a bomb had accidentally exploded while being handled by IRA members inside McGurk 's
detonated a time bomb
McGurk's Bar bombing
Military Reaction Force