Serving Garda Sergeant Maurice McCabe has started giving evidence of alleged improper termination of penalty points to TDs at a private sitting of the Public Accounts Committee today.
A public hearing last week was told of fresh claims that more than 200 senior Garda officers inappropriately wiped penalty points from driving licences.
The whistleblower - with 28 years’ experience in the force - told TDs that his life, career and family have been destroyed by the scandal.
A source close to Sgt McCabe confirmed this morning that he would be attending the committee after he received assurances from Garda management late yesterday that doing so would not jeopardise his job or open him to the possibility of disciplinary action.
It is understood Sgt McCabe would not have given evidence if his appearance before the PAC threatened his job.
The hearing started at 2pm and is expected to run for at least three hours.
Committee member and Independent TD Shane Ross said he had misgivings about Sgt McCabe’s evidence being heard in private, but said this was what the garda had requested.
Mr Ross said the PAC would be failing in its duty in relation to an issue of significant public interest if it succumbed to outside pressure to end the inquiry.
He also said it was possible some of the evidence given by Sgt McCabe may become public in the committee’s report on the matter
Garda commissioner Martin Callinan branded the claims disgusting during an appearance before the PAC last week and he has concerns that the parliamentary body was overstepping its remit.
Earlier this week, Minister for Justice Alan Shatter stepped in to refer the controversy to the Garda Ombudsman as a matter of public interest.
Mr Shatter claimed he did not have the power to take the unusual step until it had become political.
Mr Callinan had threatened legal action against the PAC over its pans to hear evidence from the whistleblower, but withdrew the threat yesterday after the watchdog agreed to hear the evidence behind closed doors.
“While I continue to have reservations about this matter, I note that the meeting will be held in private,” he said.
“I note too that it appears to be the intention to confine the questioning of the person concerned and, in particular, that person will not be able to make allegations against his colleagues or members of the public.
"Despite my reservations, I believe that, in all circumstances, it would not be in the public interest for An Garda Siochana to pursue the question of legal proceedings against an Oireachtas Committee."
Mr Callinan said the consequences of any legal action, were it successful, would have ramifications well beyond the ongoing penalty points fall-out.
Mr Callinan vowed the force would fully co-operate with the inquiry.
Additional reporting: PA