Bertie Ahern has been developing a memory problem in recent years, and there are no signs of it getting better. The situation has deteriorated to the point where the Taoiseach now is vulnerable to the charge that he misquotes the question he was asked when he seeks to justify a Dail statement.

The current political upset is all about the Charlie Haughey years and what happened to the State-funded party leader's allowance between 1983 and 1991 when Mr Ahern was a co-signatory of the account along with Ray MacSharry and Mr Haughey.

Two years ago, it seemed the matter had been safely ring-fenced when Dick Spring was handed off after he complained the allowance had not been specifically included under the terms of reference of the Moriarty tribunal. At that time, responding to a letter from Mr Spring and a Dail motion, both of which referred to the period from 1983 to 1992, Mr Ahern provided reasons why the account was above suspicion.

Referring carefully to the 1982-87 years, the new Taoiseach declared: "In so far as I could with little available records, I am satisfied, having spoken to the person who administered the account, that it was used for bona fide party purposes, that the cheques were prepared by that person and countersigned by another senior party member.

"Their purpose was to finance personnel, press and other normal supports for an Opposition leader. There was no surplus and no misappropriation. The person involved had sole control of the account . . . I have spoken to her at some length. She has served many Taoisigh beginning with Jack Lynch. We consider her to be totally honourable."

We now know that a £25,000 cheque from this account, countersigned by Mr Ahern, made its way into an Ansbacher deposit, to the benefit of Mr Haughey, in 1989. Last week, courtesy of Moriarty, we were told two cheques, amounting to £16,000, were used to buy fine shirts in Paris for Mr Haughey.

A further two cheques went to pay debts incurred by John Ellis TD, who was threatened with bankruptcy. Other cheques, amounting to £82,528 went to pay the medical expenses of the late Brian Lenihan.

Further revelations followed yesterday when the Moriarty tribunal advised a punch-drunk public that a further £75,000 had been drawn on the leader's account in 1986 to pay Mr Haughey's personal bills.

It would appear Mr Ahern has no recollection of any of these cheques, even though many of them bear his signature. The explanation offered is that they were signed in advance, as blank cheques. The matter has become so confused that the Moriarty tribunal is preparing to recall Ms Eileen Foy, the official who had charge of the account, to expand on her earlier evidence. Mr Ahern is also expected to be recalled.

With a weather eye to such a juicy development, John Bruton and Ruairi Quinn climbed onto their podiums and demanded that Mr Ahern correct the Dail record of 1997 and May 1999.

But Mr Ahern wasn't playing that game. He had given all the relevant evidence before the Moriarty tribunal, he declared. As for his Dail reply, it referred to Mr Haughey's time in opposition, he said, and followed consultations with Ms Foy.

These matters were now being reviewed by the Moriarty tribunal as they examined how the funds had been used and he had no intention of cutting across or duplicating the work of the tribunal. His Dail statement had been his best assessment of the situation at the time, but when the tribunal made its report, they could deal with matters then.

Ruairi Quinn suffered an attack of biliousness at the notion of having to wait another year or so before getting to grips with the situation. There was, he said, a time-honoured tradition that anyone who misled the Dail came in and corrected the record as soon as possible.

But the Taoiseach wasn't biting. The Dail record stood.

Unfortunately for him, the Dail record is based on errors of fact and of recall, as has been demonstrated by the Moriarty tribunal. As for Mr Ahern's reply of last May, it spoke of a "question" from Mr Spring relating to the period 1982-87. There was no such question: there was a letter and a Dail motion, and the period was from 1983 to 1991. Not that it matters much at this stage as the Moriarty investigation grinds on.

But lapses of memory are becoming increasingly common these days, at all levels of society. Why should politicians be immune to the virus that has made colanders out of the memories of bankers, Revenue Commissioners, senior civil servants and businessmen? And they are not, as we discovered some weeks ago, when a series of former finance ministers paraded their ignorance of tax evasion before the Dail Committee of Public Accounts.

Even before that, Mr Ahern was showing signs of memory loss. There was his failure to tell the Dail or the Tanaiste, Mary Harney, about the Rennicks payments to Ray Burke. And his statements relating to the appointment of the former minister for foreign affairs were seriously flawed. He "disremembered" he had appointed his brother-in-law as a Revenue Appeals Commissioner.

And there were dust-ups with Ms Harney that nearly brought down the Government. These concerned his failure to recall details of his contacts and dealings with property developer Tom Gilmartin, and his involvement in the Sheedy affair.

A pattern certainly exists. John Bruton remarked with some satisfaction that they could return to the party leader's allowance at a later stage.