On one occasion in 1972, the Fianna Fáil government stationed hundreds of armed troops at the rear of Leinster House, with orders to shoot to kill if they came under attack, former cabinet minister Mr Des O'Malley told an Oireachtas sub-committee hearing yesterday.
Mr O'Malley, who was minister for justice at the time, told the Oireachtas sub-committee which is holding hearings into the second Barron report on bombings in the Republic in 1972/73 that this period was one of "great tension and fear".
He said that over 500 people had been killed in the North and South in 1972 and that the government in Dublin was facing three separate subversive organisations.
Two of the bombings investigated by Mr Justice Barron took place in December 1972, when the Dáil was debating legislation to give the Garda more powers.
"At one stage during the passing of the Offences Against the State Act, 7,000 or 8,000 people were outside the gates, in a fairly violent frame of mind a lot of the time.
"There were 300 troops here, at the back of Leinster House, at the back of the Department of Agriculture," he said.
Mr O'Malley said the soldiers had orders to shoot to kill, if necessary, and that this was the only basis on which the military authorities would permit them to be there.
Mr O'Malley said he accepted that there was not enough concern at the time for the victims of the bombings. Last week, relatives of those killed and injured expressed unhappiness to the sub-committee at the information they had received from the government at the time and in relation to the Garda inquiries.
Mr O'Malley acknowledged that "there had not been the degree of concern for the victims or relatives that one would think desirable now".
He said that one of the fundamental difficulties with criminal proceedings in this country was that injured parties or victims were often not regarded as being central to events but were considered only as witnesses.
Mr O'Malley said gardaí had made every effort to get to grips with subversives. He said the fact that they were not successful in securing convictions was a matter of regret but that it should not be thought of by relatives and victims as being for the want of trying.
Mr O'Malley said that during this period there had been "a marked lack of co-operation" between the security forces in the North and South.
He said that until the introduction of direct rule in the North, Stormont had had responsibility for security and "they had a hostile attitude towards the South and the authorities in the South".
He said there may have been co-operation between a couple of sergeants who helped each other out but there was little co-operation on a more senior level.
Questioned by the committee about the arrest of Garda Patrick Crinnion, who was found in the company of suspected British intelligence agent John Wyman, Mr O'Malley defended signing an order preventing the disclosure of confidential documents in the subsequent court case.
Mr O'Malley said that "one of the consequences [of the order] was that Crinnion and Wyman were not convicted of more serious charges".
"I was probably aware of this at the time but on balance had formed the view that it was in the public interest to protect the sources of the gardaí," he said.
Mr O'Malley criticised the visits by two Catholic Archbishops of Dublin, Dr John Charles McQuaid and Dr Dermot Ryan, to the then IRA leader Seán MacStiofain while he was on hunger and thirst strike after his arrest in 1972.
