The Prime Minister confirmed that any political party that failed to hold the rule of law would be sanctioned but said it was inappropriate to speculate who was responsible while the police were still investigating.

He was quizzed about the killing during Prime Minister Questions in the Commons by the DUP's Jeffrey Donaldson.

The Lagan Valley MP said: " I'm sure the Prime Minister will join with me in condemning the murder of Paul Quinn.

"In light of this killing of Paul Quinn, would the Prime Minister reiterate that commitment from the Government that only parties in default of their commitments will be sanctioned in Northern Ireland and not everyone else?"

A gang of nine men bludgeoned the 21-year-old to death with iron bars and pick axe handles on Saturday, breaking almost every bone in his body

Mr Quinn was known to have had run-ins with local republicans and his parents have blamed the Provisional IRA for his death.

Sinn Fein president Gerry Adams denied the claims, insisting it was linked to fuel smuggling in the area.

But Garda sources believe that the killers were IRA members.

The Prime Minister said: "This was a brutal and horrific crime. I have already talked to the first minister and the deputy first minister in Northern Ireland about this and I'm sure sympathies of the whole House go to the family.

"I echo the widespread condemnation of this atrocious event and the desire that those who carried it out should be brought to justice as quickly as possible."