Senior Government sources have confirmed that the information about the widespread taping of phone calls to and from Garda stations emerged as a result of the Sophie Toscan du Plantier case.

Ministers were told at yesterday's Cabinet meeting that Attorney General Maire Whelan had become aware of the practice at Garda stations as a result of information that emerged in the course of a case being taken by Ian Bailey against the Garda Commissioner claiming wrongful arrest.

Minister for Agriculture Simon Coveney referred to the issue during an interview in radio interviews this morning.

"What really brought this to a head though and what became an urgent situation was that some of the detail on these recordings had been applied for under a discovery application linked to an individual court case and the content of the recordings linked to that case is very significant indeed," he told RTÉ's Morning Ireland.

“The Attorney General felt the need to bring it directly to the attention of the Taoiseach last Sunday evening which she did and the Taoiseach has taken it extremely seriously since then.”

Mr Coveney added the Taoiseach got a senior counsel to advise him on how he should proceed, he then spoke to Mr Shatter on Monday evening and brought the matter to the Cabinet’s attention on Tuesday morning.”

In an interview with Newstalk radio today Mr Coveney said: “My understanding is that the content is very serious and has very serious implications and therefore the Taoiseach had to be informed and he has acted promptly and responsibly on the back of that and has announced a full commission of inquiry.”

“My understanding is that some of these tapes were requested under discovery... and are in the process of being handed over. And the content of these tapes is very, very serious,” he said.

The High Court was told on November 25th that new material had emerged in the course of the case involving around 16,000 documents some of which was in electronic form.

Senior counsel Paul O’Higgins told the court said certain fresh and unexpected material had come up in relation to matters such as phone traffic.

Mr Justice John Hedigan gave the state until March 25th, which was yesterday, to produce the material.

The matter is due to be mentioned again in the court on Friday.

In the Dáil yesterday Taoiseach Enda Kenny said that he had been told of the matter by the Attorney General last Sunday at 6pm and had spent that night and the following day attempting to verify the scale of the problem created by the information that the practice had been widespread at garda stations for almost 25 years.

It is understood that Mr Kenny took advice from at least one eminent legal figure before informing the cabinet yesterday that the practice raised questions about whether some convictions might be tainted as a result of the practice.