The chairman of the Revenue Commissioners, Mr Dermot Quigley, began last week by placing much of the blame on politicians for the Revenue's inaction on bogus non-resident accounts.
Until last year, successive legislators had failed to grant the Commissioners the power to examine bank accounts. Without that power how could they have policed bogus non-resident accounts, the chairman, Mr Dermot Quigley, asked.
His predecessor, Mr Cathal Mac Domhnaill, made a similar point, as did several tax inspectors called before the committee. Much has also been made of the dire economic conditions that prevailed in the late 1980s and early 1990s.
Mr Quigley said the Revenue had a duty to act responsibly, and that any initiative to investigate the declarations used to open non-resident accounts could have triggered an outflow of funds which would have been detrimental to the economy.
And then there was the 1993 politically-inspired tax amnesty.
The Commissioners were vehemently opposed to this, and its existence has proved a huge setback to the organisation, even today, in administering tax collection, according to Mr Quigley.
These facts are well-grounded, and fairly represent the Revenue's position over the period being investigated by the committee. But it is in explaining why it did not take any action to stamp out the rampant abuse of non-resident accounts since the introduction of DIRT in 1986 that Revenue's defence comes unstuck.
The committee has sought to discover minutes of meetings which refer to the evasion of DIRT through bogus accounts. The only such reference appears in the minutes of a meeting held last year - after media revelations about tax evasion at NIB.
Yet over the 12 years under investigation, Revenue officials have told the committee, they were frustrated at their inability to confront the banks in relation to bogus accounts, and offered various solutions for dealing with the matter. All of these proposals were rejected.
Yesterday Mr Mac Domhnaill dismissed a substantial paper submitted by Mr Sean Moriarty in 1992 as a "minor" proposal while others, he suggested, would have had little effect on the entire problem.
As Mr Pat Rabbitte TD pointed out, none of the inspectors was harbouring any illusions that their proposals would clean up the abuse in one fell swoop, but at least they were attempting to put some pressure on the banks.
One of the Commissioners' most industrious inspectors in the financial sector, Mr Tony Mac Carthaigh, had simply suggested that the Commissioners should meet the chief executives of all of the financial institutions with a view to putting some "psychological" pressure on them to take their compliance responsibilities seriously.
"You weren't engaged in any psychological warfare against the banks. They could sleep soundly in their beds as long as you were in charge," Mr Rabbitte told Mr Mac Domhnaill.
The former chairman also insisted the Revenue never had enough actual hard evidence to approach the banks about the matter.
Yet one of the proposals that was shot down had suggested the Revenue could at least begin to make approaches to the State-owned banks, particularly ACC, which had earned a reputation for being particularly active in opening non-resident accounts. Could the Revenue Commissioners not have asked the ACC board member from the Department of Finance to find out what was going on and suggest that it might be time to tidy things up?
There were other damaging revelations, including that Mr Mac Domhnaill misled the PAC last year when he stated that the Revenue had met the financial institutions to discuss compliance with DIRT in 1991. No meetings did take place and Mr Jim Mitchell has insisted the record be changed.
Mr Quigley disputes the version given by the Comptroller and Auditor General of what he said in relation to which Revenue officials were bound by a directive (SIM 267) not to inspect bank declarations.
According to the C&AG report, Mr Quigley maintained that the directive did not apply to inspectors at the Revenue investigation branch. This has now been withdrawn, following protests by those inspectors.
And of course there is the author of the infamous SIM 267 directive. The committee has established it was written in the chief inspector's office but just who wrote it remains a mystery.
A deceased Revenue official, Mr Tony Brown, was alleged to be the author both by a senior tax inspector and by Mr Mac Domhnaill. However, Mr Quigley has now clarified that Mr Brown never worked in that section. The committee has given the Revenue one week to solve this problem.