Given the public interest in the matter and the importance of what is being inquired into, the Moriarty tribunal has all the attributes of a form of theatre, albeit with characters who would not be believed in any other genre, and plot lines which are equally outrageous.

Looked at from this perspective, Charles Haughey is not only playing the lead, he is also far and away the most experienced of all the thespians on the Dublin Castle stage.

At enthusiastic debater while studying commerce in UCD in the early 1940s, Mr Haughey spent 40 years on the political stage, playing a leading role for much of that time. He also, of course, has experience of playing from the witness-box, from both the Arms Trial in 1970 and his 1997 appearance before the McCracken tribunal.

At the end of the Arms Trial, where Mr Haughey was acquitted, the judge said that either he or the late Jim Gibbons had committed perjury. In 1997 Mr Justice McCracken, in his report, said he considered Mr Haughey's evidence to be "unacceptable and untrue". He sent the relevant papers to the Director of Public Prosecutions, who decided Mr Haughey should be charged. The trial on that charge is pending, though adjourned for an unspecified period.

At his first appearance on Friday of last week Mr Haughey seemed to ham it up, overplaying the role of the aged and ailing statesman tormented by an ungrateful public. When he returned to the witness-box on Monday, following a weekend during which there was extensive media comment about his performance, he seemed much brighter. By Thursday he seemed to have absorbed the content of his sizeable and complex file with AIB at least as well as John Coughlan SC, the counsel for the tribunal who is questioning him.

Mr Haughey showed no sign of being contrite for all that has now been revealed, and is fighting his corner. If the plot line last week was Mr Coughlan trying to establish that Mr Haughey was intimately involved in the management of his own financial affairs in the 1970s, and Mr Haughey trying to establish that the late Des Traynor conducted most of this work, only occasionally consulting Mr Haughey, then Mr Haughey finished the week ahead.

While the files contain little mention of Mr Traynor throughout the 1970s, and extensive mention of Mr Haughey, this changes dramatically in late 1979/early 1980, when the £1.143 million overdraft Mr Haughey had run up with AIB was settled with a payment of £750,000.

Mr Haughey said this was a period where he was under intense political pressure on an "hourly" basis, with enemies trying to unseat him from the position of Taoiseach to which he had been elected on December 7th, 1979. He said Mr Traynor would have been of a mind to settle his financial problem as quickly as possible and while troubling Mr Haughey as little as possible.

The crucial question of where the money came from has not been asked yet and will not now be asked until the resumption of the tribunal in September.

However, Mr Haughey has already said Mr Traynor operated on a "need to know" basis and suggested that in some instances Mr Traynor might have had a duty of confidence towards people he was involving in Mr Haughey's affairs - people who were clients of Mr Traynor.

Mr Haughey, in deference to his age and medical condition, is giving evidence for only two hours each day, four days a week. This arrangement will no doubt persist for the remainder of his evidence to the tribunal, which, with occasional adjournments, could stretch up to Christmas or beyond.

If Mr Haughey's evidence is that he cannot assist the tribunal with fresh information as to where all his money came from, as Mr Traynor handled the matter and did not inform Mr Haughey, then it is likely no new hard information will emerge.

In such a scenario, Mr Haughey's reputation is unlikely to be damaged more than it is already, save in one regard - the medical fund for the late Mr Brian Lenihan.

The tribunal has heard evidence of money intended for the fund being lodged to the Fianna Fail party leader's account, from which money was subsequently withdrawn to purchase tailor-made shirts from Paris and to pay restaurant bills. In all, up to £200,000 may be unaccounted for.

His evidence in relation to the Lenihan fund will be crucial to his reputation among those who still, despite all that has been heard, support and admire him. Overall, should Haughey's evidence be that Mr Traynor handled everything and he can be of no assistance, the issue will then be whether or not, in his report, Mr Justice Moriarty opts to believe this.

Condemnation by Mr Justice Moriarty may not be the most serious possibility facing Mr Haughey. If in his evidence he reveals that he knows who gave him money in 1979/ 1980 (apart from Patrick Gallagher who, it is known, contributed £300,000) then the matter of taxation arises. Mr Haughey paid tax on the Gallagher contribution back in the 1980s, after the payment was discovered by the liquidator to the Gallagher group. The matter was never made public.

If he knew at the time the source of the other money, as well as all the other payments which funded his lavish lifestyle during the 1980s and early 1990s, and has yet to pay tax on these payments, his position could be more serious than would be the case if he maintains that Mr Traynor never gave him the details.

To knowingly evade tax for 10 or 20 years is a more serious issue than to fail to pay tax because of ignorance concerning your affairs.

Mr Haughey did not avail of the 1993 tax amnesty, which was an offence under the terms of that amnesty for people who knew they had tax arrears. Mr Haughey's evidence to the McCracken tribunal that he did not learn of the Dunne payments until late 1993, after the amnesty, is significant in that regard.