British Direct Ruler Paul Murphy and his two predecessors have refused to attend hearings of an Irish parliamentary sub-committee on the Dublin/Monaghan bombings of 1974, it has emerged.
Paul Murphy, John Reid and Peter Mandelson, were asked to appear before the committee to discuss the Barron report into the attacks, in which 33 people died.
Mr Murphy denied there was evidence to suggest that there was a policy of collusion by the British forces in the attacks -- a point which was contradicted this week by Dublin's Minister for Justice, Michael McDowell.
Mr Murphy wrote to the committee last Friday, claiming the British government had released all relevant information, ``including that from some very sensitive sources''.
``I therefore do not believe that there is anything further of use that either I or John or Peter would be in a position to say in a hearing before your sub-committee,'' Mr Murphy wrote.
He also said that the release of further intelligence material, even privately, could ``compromise intelligence assets or the lives of sources''.
Sinn Fein leader in the Dublin parliament, Caoimhghin O Caolain TD, said the refusal of the British Government to attend the Justice Committee's hearing was a ``gross insult'' to those searching for justice.
Deputy O Caolain said: ``I don't think there's a person on the planet who does not believe there was collusion between British state forces and loyalists in the planting and detonating of bombs in Dublin and Monaghan on May 17th 1974 which left 33 civilians dead.
``The only real question is the extent of that collusion and how high up the chain of command it went.
``And given the acknowledged and proven history of the involvement of British security agencies in arming and directing loyalist death squads over many decades it is reasonable to suspect that there were agents of the British state involved in those bombings.''
Sinn Fein Vice President Pat Doherty MP has accused the British Secretary of State Paul Murphy of `continuing the decades long British policy of concealment'.
He said this policy has been evident time and again from Widgery, through Samson, Stalker and Stevens and more recently with both the Cory and Barron Reports.
``This British government under Tony Blair is continuing with this decades long policy. They are continuing to protect those within their own system who formulated and carried out a policy of state sanctioned murder.''
On Tuesday, Michael McDowell said he believed there was collusion between British security forces and loyalists over the Dublin/Monaghan bombings.
The Minister was making a submission to and answering questions from the subcommittee.
He was asked his views on collusion at the time. ``If you're talking about some members of the security forces in Northern Ireland, who saw themselves as under siege, actually colluding with people to take on their enemies, I think that collusion did exist of that kind in relation to that event,'' Mr McDowell said.
Meanwhile, the forensic scientist who examined material found at the 1974 Dublin bombings said yesterday it was unlikely that the UVF could have co-ordinated the bombs.
Dr Jim Donovan, the former Chief State Forensic Scientist, said the UVF were ``pretty backward'' in detonating bombs at the time of the Dublin/Monaghan bombings.
Loyalist bombers would have needed ``direction of some sort, to direct them how to detonate the bomb, how to assemble it, where to park it for maximum effect, how to get away'', Dr Donovan said.
His evidence supports the theory that the material used in the Dublin/Monaghan bombings may have been captured by British forces from the IRA.
Last month the retired British explosives expert, Lieut Col Nigel Wylde, told the committee that the ammonia nitrate explosives used in the attack were not in the possession of loyalist bombers at the time and that they could not have acted alone.