[2] Despite evidence to the contrary, the British security forces asserted that a bomb had exploded prematurely while being handled by Irish Republican Army (IRA) members inside the pub, implying that the victims themselves were partly to blame.

A report later found that the Royal Ulster Constabulary, the police force in Northern Ireland at the time, were biased in favour of this view and that this hindered their investigation.

In 1977, UVF member Robert Campbell was sentenced to life imprisonment for his part in the bombing and served fifteen years.

[7] The Ulster Volunteer Force (UVF) was formed in Belfast in 1966, declaring "war" on the Irish Republican Army (IRA).

Both launched armed campaigns against the British Army, the Royal Ulster Constabulary (RUC) and the government of Northern Ireland.

[12] On the evening of Saturday 4 December 1971, a four-man UVF team met in the Shankill area of Belfast and were ordered to bomb a pub on North Queen Street.

[15] At about 8:45 pm, one of them placed the bomb in the porch entrance on Great George's Street and rushed back to the car.

[18] A British Army officer, Major Jeremy Snow, was shot by the IRA on New Lodge Road and died of his wounds on 8 December.

The main theories were: The security forces promoted the idea that it was an IRA bomb which exploded prematurely (an "own goal").

[21] On 6 December, both wings of the IRA condemned the attack,[6] denied responsibility and blamed the UVF and security forces.

When put together, it included the lines:We the Empire Loyalists wish to state that we did not destroy McGurk's public house as an act of retaliation ...

Furthermore we do not require the forensic experts of the Army to cover up for us ... We shall not issue any further statements until we exterminate another rebel stronghold.

It said that two UVF members entered the pub, had a drink and asked the barman to mind a package while they "ran an errand".

The 4–5 December 1971 report said of the bombing: "Just before the explosion a man entered the licensed premises and left down a suitcase, presumably to be picked up by a known member of the IRA.

A British Intelligence Corps document covering the period 8–15 December said: "It has been confirmed that it was a [Provisional IRA] bomb which was destined for another target, but exploded prematurely.

[26] On 23 December, the British Army sent a letter (signed by a lieutenant colonel) to people living in north Belfast.

"[27] In March 1976, the RUC received intelligence that linked UVF member Robert Campbell and four others to the McGurk's bombing.

He received life imprisonment with "a recommendation to serve no less than 20 years", in part for a separate conviction for the murder of a Protestant delivery driver in 1976.

[30] Relatives argued that this theory was promoted as part of a "government policy to avoid publicly acknowledging the loyalist campaign of violence".

The plan was allegedly to start a feud between the two IRA factions, which would both divert them from their campaign against British forces and drain their support.

The report also found that RUC gave "selective" and "misleading" briefings to the government and media, which furthered the idea that it was an IRA bomb.

Ombudsman Al Hutchinson said: "Inconsistent police briefings, some of which inferred that victims of the bombing were culpable in the atrocity, caused the bereaved families great distress, which has continued for many years".

[33] On 6 December 2012, Scottish Labour MP Michael Connarty—whose uncle was killed in the bombing—claimed in Westminster that then-Prime Minister Edward Heath "may have been involved" in wrongfully blaming the IRA and spreading the story.

[34] Connarty also urged David Cameron, prime minister at the time, to apologise to victims and launch a full investigation.

[6] The victims' relatives carried fifteen wreaths to the new memorial, and used the occasion to demand an investigation into alleged British involvement in the attack.