The Barron Report has found there was widespread collusion between British security forces and loyalist terrorists who carried out a series of attacks in the 1970s, according to the Joint Oireachtas Committee on Justice.
The final report of the Committee on Mr Justice Barron's Commission of Inquiry says there is no doubt that there was collusion "between the British security forces and terrorists" in nine terrorist attacks on both sides of the border in the 1970s that resulted in 18 deaths.
The atrocities that the report covers include the bombing of Kay's Tavern in Dundalk, the 1976 Castleblaney bombing, the Dublin Airport bombing, the gun and bomb attack at Donnelluy's Bar, Silverbridge, Co Armagh, the attack on the Miami Showband and incidents in counties Down and Armagh
"We now have enough information to be fully satisfied, not only that it occured, but that it was widespread," the committee's report concludes.
Chairman of the committee, Mr Sean Ardagh said that they did not know the full extent of collusion but that he was "fully convinced that many people were involved in it."
Rather than calling for a public inquiry now the committee concluded the best course of action was a detailed Dáil debate which "will hopefully be a catalyst for further action", said Mr Ardagh.
It hopes that this would then lead to a commission of inquiry where both governments would cooperate in "good will" similar to the investigation by Canadian Justice Peter Cory into terrorism during the Troubles.
Speaking after the publication of the committee's report Taoiseach Bertie Ahern said: "The findings in this report regarding collusion are deeply troubling and a matter of most serious concern.
"They paint a very disturbing picture."
He said the Government had consistently pressed London for its cooperation and had made contact again today.
"It is absolutely essential that the British Government examine the findings of all of these reports, as well as the forthcoming MacEntee Report [into the Dublin and Monaghan bombings], and that it fully co-operates with all investigations into the serious issues that have arisen."
Mr MacEntee's report is expected on 10th December.
The report also suggests that collusion was known about at the highest levels of the British Government and that Margaret Thatcher and Conservative Party colleagues were briefed about it in 1975 by Labour prime minister Harold Wilson.
At that meeting the "future prime minister was informed that the RUC was not to be trusted." The minutes of the meeting also say that Mrs Thatcher and the others were informed that "the UDR was heavily infiltrated by extremist Protestants who would not be relied upon to be loyal in a crisis."
Mr Ardagh noted that Mr Justice Barron had no cooperation from the Northern Ireland Office with his investigation but that PSNI Chief Constable Sir Hugh Orde openly came before the committee and that this might signal a change in approach by authorities North of the border.
Fine Gael leader Enda Kenny said the Taoiseach should immediately relay the report oto British Prime Minister Tony Blair.
"Given the British Government's failure to provide any meaningful cooperation to Mr Justice Barron's inquiry, the Taoiseach should demand that the Prime Minister now agrees to provide the necessary cooperation, within the spirit of the new East-West relationship established by the Good Friday Agreement."