Ireland could face demands for millions of euro in reparations after Justice Henry Barron's report into the 1974 Dublin and Monaghan bombings report.
The bombings in Dublin and Monaghan on May 17 1974 killed 33 people including an unborn child.
It was the single bloodiest day in the history of the conflict.
The long-awaited report into the bombings by Justice Henry Barron said there were ``grounds for suspecting'' that the bombers may have had assistance from the British security forces.
It was also revealed last week that inaction by the government of the day led to further murders of Irish citizens by the same bombers.
The report says that the 1973-1977 Fine Gael and Labour coalition did nothing when the British authorities gave it the names of the bombers; and that crucial files from the Department of Justice and the garda are ``missing''.
Relatives of the victims urged this weekend that four key politicians from that government - Fine Gael's Garret FitzGerald, Liam Cosgrave and Paddy Cooney, and Labour's Conor Cruise O'Brien - should be summoned before the Dail Committee. Gardai are also studying the report.
Barron suggests that some of the bombers went on killing Irish citizens, in both the North and the South, even after the Irish government had been informed of their identities.
He also confirms that the government was terrified of the perceived menace to the institutions of the 26-County state from republicans.
Evidence that British Crown forces were involved in attacks on Irish civilians could have boosted the IRA and undermined support for the fragile coalition government.
But the report was criticised for not giving definitive answers on collusion.
``It's a red herring to say that the Northern authorities were not involved at a senior level. Many of the loyalists involved in the bombings were members of the RUC and the UDR,'' said filmmaker Paul Larkin, who has researched the events of May 17, 1974.
Speaking to the Sunday Business Post, he said: ``It also claims that the loyalists involved were later interned. That's not the case. Only one loyalist had been interned and that was on a separate charge. The whole lot of them were walking around Portadown.''
However, the judge was hampered by stonewalling from the British government, an obstacle that would hinder any future judicial inquiry.
Barron acknowledged that he had encountered the same ``obstructionism'' from British army and police agencies which hampered the work of London police chief John Stevens in his probe into collusion in the North.
Justice for the Forgotten, a group of relatives of the Dublin-Monaghan bombings, said the relatives were prepared to look at all the options to a full judicial inquiry.
``We'd like things to move as quickly as possible - but it must be thorough. We have so many members who are elderly,'' said spokeswoman Margaret Urwin.
``Many of them are in their eighties and they need closure quickly.''
Urwin said Barron's report failed to find proof of high-level British collusion with loyalists because he was prevented from doing so. ``It seems the British government didn't cooperate with Barron at all. While the PSNI provided him with documents, there was no cooperation from government departments or the Northern Ireland Office.
``It is ironic that Tony Blair should be waging his war against terrorism with regard to al-Qaeda and Saddam Hussein and yet his government refuses to cooperate with an inquiry set up to deal with such a serious act of terrorism.''