A Fine Gael member of the Dáil’s Public Accounts Committee approached Taoiseach Enda Kenny following its hearings on penalty point cancellations earlier this year and told him that the Garda whistleblower, Maurice McCabe, “would be vindicated”.

John Deasy raised concerns with the Taoiseach on February 20 following the committee’s meeting in private with Mr McCabe — whom he found to be credible — and public hearings with the then Garda commissioner, Martin Callinan.

The Waterford TD expressed a view that there were “deficiencies” in the report on penalty point cancellations compiled by Assistant Commissioner John O’Mahony and that the then-justice minister, Alan Shatter, “needed to deal with this in a different manner”.

Having not heard back from Mr Kenny, he wrote to him on March 21, saying the issue should be dealt with “for once and for all”.

Referring to Mr Shatter, Mr Deasy said that Mr Kenny should “question Alan’s handling of the entire affair”.

In the letter, seen by the Irish Examiner, he wrote: “What I and many of my colleagues don’t understand is why Alan [Shatter] would treat the whistleblower in the manner he has in the last couple of months.”

He told the Taoiseach he did not condone the taking of information from the Pulse system. “But I do think some consideration needs to be given to the fact that the whistleblowers attempted to deal within official channels, but that those official channels did not operate correctly.”

The revelations come as pressure increases on Mr Kenny to explain the sequence of events leading up to the resignation of Mr Callinan on March 25.

Fianna Fáil said the outgoing secretary general of the Department of Justice, Brian Purcell, is being “kept sweet” by holding onto his €200,000 salary despite moving aside.