Meanwhile, his colleague Finbarr Hickey said he was pleased evidence that he “had no hand act or part in any collusion” was accepted.
Mr Colton was one of three named officers cleared by the Smithwick Tribunal of colluding with the IRA on the day Chief SuptHarry Breen and Supt Bob Buchanan were murdered.
But he dismissed other findings against him by Judge Peter Smithwick.
“Retired Sergeant Leo Colton respects the integrity and the hard work carried out by the chairman and the tribunal team but totally rejects the finding that he was involved with the IRA,” he said in a statement issued through his solicitors.
“Leo Colton was not, is not and never would be involved with the IRA or any other subversive organisation.”
Judge Smithwick found that Mr Colton assisted the IRA in 1995 and 1996 by getting his former colleague, Mr Hickey, to sign false passport applications.
“This is a relatively significant form of assistance and suggests to me that members of the Provisional IRA reposed considerable trust in Mr Colton at that point,” the judge said.
However, he said that he did not think there was sufficient evidence to establish there was a relationship between Mr Colton and the Provisional IRA as far back as 1990.
Mr Colton resigned in 1991, days before a disciplinary inquiry was due to be held against him over the issuing of the trade plate.
The former garda was on duty in Dundalk on Mar 20, 1989, the day the RUC officers were ambushed.
However the tribunal found neither he nor two other former gardaí questioned — Mr Hickey or Owen Corrigan — were involved with any collusion on the day of the double murder.
Meanwhile, Mr Hickey, also a former garda sergant, said he was pleased that the tribunal accepted his evidence that “I had no hand act or part in any collusion”.
In a statement issued by his solicitor, he said: “From my first contact with the tribunal I have co-operated completely with it, presented myself to give evidence, and been subject to cross-examination, in public.
“I am pleased that the tribunal has accepted my evidence that I had no hand act or part in any collusion.”
In particular he welcomed the finding that he “was not in a position to pass information to the IRA which facilitated the ambush on Edenappa Road”.
He also particularly welcomed the conclusion that “I accept that there was no relationship between the provisional IRA and Finbar Hickey, that he was not a member of that organisation or a sympathiser with its cause, and that while he somewhat foolishly and naively did not advert his mind to the possible uses of the false passport application forms, he did not deliberately assist the IRA with the procurement of false passports.”
He said the tribunal process had “been immensely stressful on my family and me, with my name being repeatedly linked with the allegation under investigation”.
“I hope that responsible journalists will give equal prominence to the findings of the tribunal absolving me of any wrongdoing.”