Are we likely ever to know what all this delving into the dark underbelly of political corruption will cost? Not at all, according to the one man who should know, the general secretary of the department of finance David Doyle. He says nobody knows how much the costs of third-party witnesses will be because nobody keeps a record. It's only when the bills arrive in the post that they can begin the sums.

Tribunal-land is starting to look like the World According To Donald Rumsfeld. The former US defence secretary's fabulously knotty "known knowns" quote is worth recalling in this context.

"As we know, there are known knowns;

there are things we know we know. We also know there are known unknowns;

that is to say, we know there are some things we do not know. But there are also unknown unknowns - the ones we don't know we don't know."

What do we know? Lawyers are earning as much as Euro2,500 a day on the Mahon tribunal. The big names have so far trousered Euro6m-plus a head. They have earned much of this by asking Frank Dunlop to name the councillors to whom he paid amounts so insignificant, that the barristers themselves wouldn't get out of bed for it, let alone spend a day in a tribunal.

While nobody wants those who were bribed to rezone land, and those who undermined the entire planning process in Dublin during the '70s and '80s to go unpunished, there is no doubt that an inordinate amount of time and money has been wasted going after small-fry rather than recording the scale of the corruption in more general terms. At the same time, the exposure of the extent of Charles Haughey's corruption, and that of Ray Burke and George Redmond, as well as the late Liam Lawlor are all now "known knowns" - bringing with them a sort of national closure after the convulsions their corruption caused.

Last week's row is all about that big "known unknown" - the size of the tribunal lawyers' fees.

Tribunal lawyers are the real fat cats of our society, and taking them on is a populist move. The Oireachtas decided almost three years ago that their fees should be reduced, and this latest spat is, in reality, little more than a good old-fashioned industrial-relations showdown.

The deadline for the old fee structure is late March, so lawyers and government have to square up to each other mano-amano before agreement is reached.

Legal A1/4ber-egos The difference is that, unlike most workers looking for pay agreements, the lawyers - rather like the medical consultants - have a massively over-inflated view of their worth. It is an A1/4ber-ego born of government failure to terminate their self-regulating monopoly. Their threat to walk out of the tribunals is an insult to the principle of public service.

The tribunals will cost a lot - but how much "a lot" means depends on how much you have. After all, government coffers have been so flush with unexpected tax income in the past decade that, over the past decade, the Fianna FA il-PD coalition has been prepared to see the Luas go Euro95m over budget, spend Euro231m on the, as yet unusable, PPars accounting system for the health service, waste Euro57m (so far) on the e-voting fiasco.

For the government, the "unknown unknown" is how all this will play with the electorate before an election.

The public mood is certainly for an end to the tribunals. The lawyers have had their snouts in the trough for long enough. The government must either cut the fees or insist that the tribunals report within a certain time frame.

Either way, a clearly defined amount of money must be involved.

At the same time, they cannot be seen to scupper the Quarryvale module of the Mahon tribunal, particularly because developer Tom Gilmartin's allegations go to the heart of the actions - or inaction - of many leading Fianna FA il ministers and ex-ministers. To stop at this point would be madness electorally.

Meanwhile, as usual, nothing has been done to change the planning framework under which massive amounts of money were made through rezoning.

The same incentives are still there to make a fortune out of rezoning, and Dick Roche's tentative moves to force developers to "use or lose" their land are but a mouse's roar from the "known known" that's needed in terms of planning reform. . .