All files drawn up by a whistleblower into alleged tax evasion by former senior politicians were fully examined and followed up, the chairman of the Revenue Commissioners has said.

Addressing the Dáil Public Accounts Committee, Josephine Feehily said all material on the issue which were referred to Revenue by the Minister for Jobs and Enterprise were pursued “wherever it took us”.

The committee questioned the Revenue Commissioners about allegations made by a serving official in the Department of Jobs and Enterprise Gerry Ryan about tax evasion by former senior political figures.

Mr Ryan had served as the “authorised officer” under company law who investigated Ansbacher accounts in the Cayman Islands.

He contended in a dossier given to the committee last month, under new whistle blowing legislation, that a number of named former senior politicians had held such offshore accounts.

He maintained that details of these secret accounts had never emerged as part of previous investigations in Ansbacher.

Independent TD Shane Ross said Mr Ryan had maintained that Revenue along with a number of other State agencies had not carried out any meaningful investigation into this alleged tax evasion.

Ms Feehily disagreed and said she was surprised at these claims.

She said between September 1999 and February 2011, Revenue had received extensive reports, information, books and documents from the Minister for Jobs, Enterprise and Innovation relating to Ansbacher accounts.

“All of this information has been examined and followed up and is included in the cases which were investigated by the Ansbacher Project team (established by the Revenue Commissioners).”

She said Revenue officials had told her that many “helpful meetings” had been held with Mr Ryan over the years.

However she said that under tax confidentiality rules she could not share internal Revenue files with Mr Ryan on its subsequent actions.

Ms Feehily rejected any suggestion that there had been political interference in the operation of the Revenue Commissioners.

She said on foot of its investigation into Ansbacher a total of 289 cases were identified.

“As of now, 283 cases have been finalised. Of the remaining 6, 5 have made payments on account and 4 are under appeal.”

She said 138 of the finalised cases had yielded €113 million in tax, interest and penalties.

She said in addition to the direct Ansbacher inquiries there had been two “spin-off” investigations carried out by the Revenue Commissioners.

“The combined yield from the Ansbacher investigations and the two spin-offs will likely exceed €250 million”, she said.

Asked why no-one had been prosecuted, she said prosecutions had been actively considered in a number of cases but these did not go ahead for a number of reasons.

Ms Feehily said one significant impediment was legislation which dictated that proceedings had to be instituted within 10 years of the alleged offence being committed.

She also maintained that the availability of relevant original documentation was an essential element for a successful criminal prosecution.

“That element was largely missing”, she said.

Ms Feehily said there were few original documents available and there was “no legal mechanism to compel Cayman entities to produce documents or their employees to give evidence”.

Questioning Ms Feehily, Sinn Féin deputy leader Mary Lou McDonald said that at the core of Mr Ryan’s allegation was that in late 2003 or early 2004 he had discovered a “secret ledger” and that it had not been investigated at all.

Ms McDonald asked Ms Feehily whether it was the case that this information had landed on Revenue’s desk and that the commissioners had said “we know this already, we are on top of this”, or whether they had decided the information in it was “irrelevant”.

Ms Feehily said this was “absolutely not” the case. She said that at the conclusion of the Ansbacher investigations, Revenue had access to a quarter of a million documents, had interviewed bank officials and had considerably greater powers than Mr Ryan had as authorised officer.

Information received from Mr Ryan “may have helped in terms of providing additional insights” but Revenue had established the case base already.

“I’m not in a position to comment on the narrow question you are asking about a particular ledger, I don’t know. But what I am satisfied is that we didn’t get any new information, we didn’t get any new cases.”

Ms Feehily said the information Revenue had received from Mr Ryan did not add any new cases to the Ansbacher project.

She said, however, the authorised officer’s reports had brought 27 cases to Revenue that it did not have from another source. Ten of those had resulted in an additional tax liability.

She told the committee there would have to be a legal basis for a new dossier of any description to be given to Revenue.

Asked by Ms McDonald at what point in the process someone would be contacted and made aware that Revenue was investigating information received about them, Ms Feehily said could not discuss the Ansbacher cases.

But she said: “Perhaps never.”

Ms Feehily said she was being careful because there were “lists of names floating around”.

She was not going to discuss a process that might leave her exposed under legislation to a criminal charge that some inference could be drawn from a remark she made at the committee hearing.

Earlier, Fine Gael TD John Deasy accused Ms McDonald of using the Dáil Public Accounts Committee for political ends.

He said her actions were affecting the working of the committee which was suppose to act in a bi-partisan manner.

“You need to stop here,” he said.

Ms McDonald said she was perfectly entitled as a public representative to act as she did when she named in the Dáil some of the former senior politicians accused by a whistleblower of tax evasion.

She said she was answerable to those who elected her and not to a Fine Gael member of the Public Accounts Committee.

Mr Deasy said the impression had been given to the public that the committee had exhausted all options available to it in relation to investigating the allegations if tax evasion made by the whistleblower.

He said the legal adviser to the committee had set out two options; interviewing the Revenue Commissioners and applying for a resolution if the Dáil to allow it to deal with the matters concerned.

Joe Costello of the Labour Party said it was totally untrue to say the committee had reached the end of the road.

Ms McDonald said the legal advice given to the committee had been very consistent that it could only operate within narrow confines.