It's been more than 14 years since the earliest interim reports of what was then known as the Flood Tribunal were published. In the High Court last Thursday, the tribunal was forced to admit that its findings against two men back then were "unlawful" and would now be quashed.
At issue was the reliability of the so-called Tribunal of Inquiry into Certain Planning Matters and Payments' star witness James Gogarty, whose testimony was often the sole evidence against particular individuals. The tribunal, it has now been revealed, suppressed material that would have cast doubt on his credibility, and has also been accused by those affected of having "encouraged" Gogarty to make damaging statements about people that were not even relevant to the case.
This whole turn of events is extraordinary. The Mahon Tribunal, as it subsequently became known, was the longest, most expensive public inquiry in Ireland's history, with costs estimated at upwards of a quarter of a billion euro.
If, years later, its rulings are still being overturned, it raises awkward questions about the efficacy of tribunals as the best way of throwing light on issues of public concern.
With another one getting under way this week - the Disclosures Tribunal into the whispering campaign that was mounted against garda whistleblower Maurice McCabe - that question has never been more relevant; and no one seems more aware of it than Supreme Court judge Peter Charleton, whose opening remarks on Monday in Dublin Castle emphasised his desire for a swift and decisive outcome to his hearings.
Charleton was mindful of the cost to the public purse of these investigations, adding that every lie told to him would be a drain on those resources, and the fact that the opening statement came so swiftly on foot of the establishment of the tribunal may be a comforting indication of how he intends to proceed.
Right now, the intended nine-month time frame does not seem unrealistic, but tribunals have begun with similarly laudable ambitions, only to vanish into legal quagmires reminiscent of the infamous suit of Jarndyce and Jarndyce in Bleak House, which was "so complicated that no man alive knows what it means".
Dickens's fictional case was based on a real row over a will which dragged on for 117 years, only to expire when the estate ran out of money to keep paying the legal fees.
Our tribunals have not been so wasteful, and some costs have been recouped by the Criminal Assets Bureau and Revenue Commissioners as a result of rulings; but it remains undeniable that the expense and length of tribunals has tended to run amok.
Arguably there's no alternative. Voters in 2011 rejected an amendment to the Constitution which was called "in order to provide for the Houses of the Oireachtas to conduct full inquiries" in matters of "general public importance", fearing perhaps that a government could use these investigatory powers as a political weapon in future against its enemies and critics. But if tribunals are too cumbersome and costly, and Dail inquiries open to abuse, what is the alternative?
The only options are a smaller-scale commission of investigation, such as that established to look into the Magdalene laundries, or a police-led criminal probe such as that faced by French presidential candidate Francois Fillon over claims that his relatives were paid for work they never did.
The first option was indefensible in the case of Maurice McCabe, who flatly rejected talk of a private investigation; and the guards can hardly be entrusted to investigate themselves. It could also be that some issues are so complex, only a tribunal will do.
The Chilcot Inquiry in Britain into the Iraq War was such a case; but that example does raise the question of why an inquiry into so vast a subject could take seven years from establishment to completion - a wait considered inordinately long by an impatient British public, which didn't know how fortunate it was - when more superficially straightforward matters take far longer in Ireland to bring to a conclusion.
In both Ireland and the UK, there does seem to be more of a rush now to set up public inquiries than there was in the past. Is it that ministers are increasingly terrified of making difficult decisions, even though that's what they're paid to do, so setting up a tribunal becomes an easy option, getting detractors off their backs and allowing them to put controversies on the long finger for others, preferably their successors, to deal with?
Has there ever been a minister for justice in Ireland who saw a tribunal through from beginning to end? In the case of Mahon, there were seven ministers for justice between its establishment and publication of the final report in 2012.
Tribunals tend to be most successful when confining themselves to a limited list of questions. The Disclosures Tribunal ought to fall into that category; but experience suggests that travellers can set out on a journey with the noblest of intentions, only to get lost along the way in a tangled forest as the path meanders through strange places that they never intended to visit.
Once persons of interest start surrounding themselves with legal bodyguards, it only gets more complicated, and we're soon back in Jarndyce and Jarndyce territory.
Again, Charleton has made it clear that he does not intend that to happen, but there's still a heavy weight of responsibility on his learned shoulders.
If he can conclude the Disclosures Tribunal quickly and efficiently, delivering a report that satisfies understandable public disquiet, he might even be able to restore the reputation of tribunals as the correct way to get to the murky bottom of disturbing events. If it drags on and gets bogged down in the legal thicket, then probably we need to think again about alternatives.
Especially if rulings can simply be overturned years later, making a mockery of any hope that tribunals are better placed to avoid the pitfalls into which other investigatory avenues stumble and fall.
The strongest argument for putting up with the cost and length of legal tribunals is that their findings are definitive and can stand the test of time.
If that's not even true, what are they for in the first place?