The British government supplied loyalist killing gangs with training and information which was used to target and murder civilians in the Republic and Northern Ireland, according to a former British army spy.
Speaking on RTÉ radio today, Mr Willie Carlin, a former British soldier said he had been recruited by MI5 into the ‘Force Research Unit’ (FRU) in 1974.
The FRU was a covert British army unit comprised of agents who infiltrated paramilitary organisations. FRU "handlers" advised and debriefed these agents.
Mr Carlin alleged that the purpose of the FRU was to redirect "loyalist killing gangs" away from sectarian killings towards so-called "legitimate" republican targets.
He said John Francis Green - who was killed in Monaghan in 1975 - was killed by loyalists acting on information received by the British army. "The people who killed him got their information from the FRU and they were allowed through the border.
"The route was cleared for them to kill Joe Green and they were allowed safe passage back to Northern Ireland," he alleged on the RTÉ programme.
Accusing the British government of abandoning its former agents, Mr Carlin and a group of former agents are threatening to release information claiming that the British government withheld information about "killings, break-ins, SAS activity in the Republic and information that wasn’t passed on".
Referring to the Dublin and Monoghan bombings in 1974, Mr Carlin alleged loyalists were "encouraged" and given training in bomb-making.
He continued: "operations were allowed to go ahead and people lost their lives as a result of the lack of co-operation between the two states."
He also claimed that the RUC was given information by a man known as Kevin Fulton "naming the man who made the Omagh bomb."
Three days prior to the Omagh bombing, Mr Fulton told his RUC handlers of his suspicions that dissident republicans were preparing a massive bomb.
In her report, Police Ombudsman, Ms Nuala O'Loan said Mr Fulton's information had "not been given sufficient weight" and had "not adequately been followed up", although she concluded: "Even if reasonable action had been taken... it is unlikely that the Omagh bomb could have been prevented".
Mr Carlin said that he and other former agents are due to meet with representatives of the Irish Government’s Anglo-Irish Division in an effort to get the Government to apply pressure on the British government to release information on "what was allowed to go on."