Relatives of the 1974 Dublin and Monaghan bomb victims today appealed for information into alleged British collusion in the atrocity that killed 33.
Campaign group Justice for the Forgotten said new forensic reports submitted to an independent inquiry in the Republic indicated there was a "hidden state-controlled hand" in the blast.
"A scientific assessment of bomb disposal records of bombings in 1974 contain empirical evidence that the explosives and explosive devices used in the Dublin bombs were not in loyalist arsenals," Mr Cormac Ó Dulacháin, lawyer for the group, said at a meeting at Westminster.
"These forensic reports corroborate statements, obtained by the legal team, that explosives were made available to a group known as the Protestant Action Force or Protestant Task Force by a British army officer on an operation-by-operation basis."
He said the forensic report together with correspondence and statements from the British Ministry of Defence obtained by the relatives' legal team gave rise to a "real concern" the bombings were inspired by the British Army.
Justice for the Forgotten is appealing for co-operation from the British government which it says is an "essential ingredient" in finding the truth behind the bombings.
On May 17th, 1974, three car bombs exploded in Dublin's city centre, killing 26 people and injuring over 200. A hour and a half later a car bomb in Monaghan killed seven and over 40 were injured.
An independent private inquiry into the bombings has been set up under former judge Mr Henry Barron.
The Barron inquiry's report is to go before a public hearing of the Parliamentary Justice, Equality and Women's Rights Committee later this year.
PA