Owen Corrigan, who was a detective sergeant based in Dundalk during the 1970s and 1980s, denies allegations of collusion with the IRA, and has described them as a “monstrous lie.”
The tribunal is investigating allegations of garda collusion in the deaths of two RUC officers, chief superintendent Harry Breen and superintendent Bob Buchanan, as they returned from a security meeting in Dundalk Garda station on 20 March 1989.
Mr Corrigan said that the tribunal was set up on the recommendation of Canadian judge Peter Cory, who based his decision on the evidence of “Kevin Fulton”, AKA Peter Keeley.
“He [Keeley] went to judge Cory as a result of the joint British-Irish meeting in Weston, when the Irish government were pressurising the British authorities on collusion,” Mr Corrigan said.
“The British authorities pulled him out of the hat and sent him to judge Cory.”
“That is the basis for this whole inquiry.”
Mr Corrigan said that Keeley had “made a full time profession of telling lies, including writing books.”
And he said the former agent’s allegations were “totally and absolutely off the wall and he has not an ounce of credibility.”
Mr Corrigan said that being named in the House of Commons under privilege by unionist MP Jeffrey Donaldson was “a statement of incitement in relation to my very existence”.
“I think it’s totally irresponsible of any parliamentary representative to go around issuing threats like that,” he said.
“As a member of parliament he should be ashamed of himself to incite anyone.”
Tribunal barrister Mr Justin Dillon SC said that Mr Corrigan had been named as an IRA “mole” by two individuals who did not know each other, Mr Keeley and John McAnulty, a businessman who was abducted and kidnapped by the IRA in 1989.
Mr Corrigan has told the tribunal that for medical reasons he is only able to give evidence for two hours a day, two days a week.
Mr Dillon said he expected to complete his examination for Mr Corrigan next Tuesday, the next day the witness is able to attend the tribunal.
Based on questioning of other barristers by tribunal chairman Mr Peter Smithwick about the expected length of their cross-examinations, the tribunal is likely to continue until the end of July.