The never-ending Flood-Mahon Tribunal has been the most costly so far with a bill to date of ?53m.

Beef Tribunal (?27m) - 1993 Widely regarded as 'the daddy of them of all', the Beef Tribunal was the first inquiry to probe the relationship between big business and politics.

It had drama and big names. But it lacked the forensic ruthlessness of those which followed when it came to probing political donations.

This tribunal ultimately wrecked the Fianna Fail/PD coalition when Mr Reynolds and Mr O'Malley went head-to-head over export credit insurance given to the Goodman group.

Finlay Tribunal (?4.7m) - 1997 This was established to probe the contamination of donated blood supplies.

The campaign and tragic death of Brigid McCole led to the establishment of this inquiry.

In all more than 1,600 women and men were affected by the supplies.

Mr Justice Finlay was scathing but, although he clearly established how the infection of the blood happened, he was unable to determine why.

Lindsay Tribunal (?46m) - 2002 This tribunal was set up in 1999 and effectively pursued another avenue of inquiry stemming from the Finlay probe.

The remit was to investigate how people with haemophilia became infected with HIV and hepatitis C through contaminated blood products supplied by the BTSB. Public hearings began in May 2000. Haemophiliacs wanted to know whether the BTSB, along with the Department of Health, concealed the extent of the State's role in infecting haemophiliacs with HIV.

The question was left hanging, depending largely upon what interpretation was put on the tribunal's findings.

McCracken Tribunal (?6.6m) - 1997 After decades of rumour, innuendo and speculation, the McCracken Tribunal delivered the first decisive blow to the reputation and credibility of Charles J Haughey. Mr Justice Brian McCracken proved Mr Haughey had got over ?1m from Ben Dunne. The inquiry was set up following the disclosure in the Irish Independent that Dunnes Stores had paid for a lavish house extension for former minister Michael Lowry when he was a TD.

Mr Lowry resigned from Cabinet, and within days stories emerged about the ?1m given to Mr Haughey.

It also lifted the lid on the infamous off-shore Ansbacher accounts.

Moriarty Tribunal - (?24m to date) Heading for its 10th year, the Moriarty tribunal was expected to have been a short, sharp affair.

Asked to pick up the threads from unfinished business that was outside the remit of McCracken, the evidence given to the tribunal established that for most of his political career Mr Haughey was a tax cheat and a kept man. The longevity of this tribunal is largely due the emergence of a money trail between Michael Lowry and Denis O'Brien, who headed up the ESAT consortium that won the lucrative second mobile phone licence.

The licence was awarded by Mr Lowry when a minister, but all the players have denied bribery. It has yet to produce a report on its findings.

Flood-Mahon Tribunal - (?53m) Like Moriarty at the other end of the Dublin Castle complex, this tribunal is entering its 10th year. It has delivered a shocking portrayal of corruption in the planning process. Mr Justice Feargus Flood crossed a rubicon in Irish public life when his first major report damned former minister Ray Burke as corrupt, producing astonishing evidence of payments off-shore.

The inquiry destroyed what was left of Liam Lawlor's political reputation, showing extensive, secret off-shore payments and ultimately forcing him out of politics. A further report established that former assistant Dublin city and county manager George Redmond was also in the pay of builders. Equally sensationally, the tribunal resulted in former lobbyist Frank Dunlop cracking and spilling the beans on scores of corruptpayments. It is expected to complete its work next year.

Dunne Inquiry - (?11.5m) 2005 This inquiry was established to examine issues and practices regarding organ retention in the country's main paediatric hospitals. The Government brought the non-statutory inquiry to a close in March last year.

It was originally expected to last six months but went on for five years. The campaign group for those affected, Parents for Justice, withdrew from the inquiry in 2002, saying it had no confidence in its work.

Madden Inquiry (?228,000) 2006 Political dissatisfaction with the outcome of the Dunne Inquiry led the Government to ask Dr Deirdre Madden, an expert in medical law and ethics, to complete the investigation.

Her 140 pages of conclusions into post-mortem practices blamed the 'doctor knows best' culture for the way in which parents were never told organs were removed.

Laffoy Commission into Child Abuse - (?30m) This is one of the most harrowing inquiries, dealing with the most sinister and darker sides of Irish society.

It almost collapsed in 2003 when Ms Justice Laffoy resigned. She carefully castigated the Department of Education and Science, accusing it of persistently obstructing the work of the commission.

The ongoing inquiry is now chaired by Mr Justice Sean Ryan.

Ferns Inquiry - (?928,000) 2005 Established to find the truth about child abuse in the Diocese of Ferns, the inquiry identified over 100 allegations of child sexual abuse, made between 1962 and 2002, against 21 priests.

Six of the priests had died before any allegations of abuse were made against them. It concluded that both Bishop Donal Herlihy and Bishop Brendan Comiskey placed the interests of individual priests ahead of those of the community. The findings were particularly damning of Bishop Comiskey, stating that in "almost every case significant periods elapsed" before the bishop could persuade the priest in question to vacate his position and undergo assessment and treatment.

Lourdes Inquiry - (?2.3m) 2006 This inquiry, headed by Judge Maureen Harding Clarke, was established following Dr Michael Neary's being struck off the medical register after being found guilty of professional misconduct in relation to 10 patients at Lourdes Hospital, Drogheda.

At the core of the inquiry was the appalling treatment of women who had unnecessary hysterectomies.

It found that a total of 188 peripartum hysterectomies were carried out at Drogheda from 1974 to 1998. Of the 188 cases, 129 cases have been attributed to Dr Neary.

The rate of caesarean hysterectomies at the hospital over that period was one for every 37 caesarean sections. In contrast, the rate at other hospitals of a similar ethos, ranged from one per 300 to one per 254.

The numbers of caesarean hysterectomies carried out by Dr Neary in 1978/79 caused the then matron some concern but the inquiry found her concerns were not heeded.

Barr Tribunal (?6m) 2006 The Barr Tribunal was set up in July 2002 to inquire into the facts and circumstances surrounding the fatal shooting of 27-year-old John Carthy at Abbeylara, Co Longford, on 20 April, 2000. Mr Justice Barr found there were critical errors and negligence by gardai during the 25-hour siege.

In his 740-page report stated he was satisfied that responsibility for Mr Carthy's death rested primarily with the scene commanders, and to a lesser extent with the Emergency Response Unit commander.

The judge recommended that there be an urgent review of garda command structures and said there needed to be training.

Morris Tribunal (?12m) Now in its fourth year the Morris Tribunal has delivered a series of damning reports on the gardai, especially the activities of the force in Donegal. It has done to the reputation of the Garda Siochana what the McCracken, Moriarty, Flood and Mahon tribunals did to certain politicians. It was asked to investigate the death of cattle dealer Richie Barron of Raphoe, Co Donegal, on October 14 1996 with particular reference to allegations of harassment of the McBrearty family and associates by gardai.

The findings to date have shocked the public and politicians as Mr Justice Morris painted a picture of a force riddled with negligence and officers found to have planted weapons, ammunition and hoax explosives. Already it has resulted in far-reaching changes to the force.

Barron Inquiry (?2.2m) This was set up to inquire into the Dublin and Monaghan bombings and in December 2003 Mr Justice Barron criticised former Taoiseach, Liam Cosgrave, for not passing on information from British prime minister Harold Wilson in 1974 that a number of UVF members suspected of involvement in the bombings which killed 33 people had been interned.

The probe has been hampered by the lack of co-operation from British intelligence services. Mr Justice Barron also examined the sectarian killing of Seamus Ludlow.

Commission of Inquiry into Dublin and Monaghan Bombings (?800,000) This probe was set up in May 2005 to investigate, in private, matters relating to the Garda investigation of the bombings in 1974.

Last month, the Commission announced it has substantially completed its work.

Breen and Buchanan Tribunal (?70,000) This was set up in May 2005 to establish whether there was garda collusion in the murder by the IRA of two senior RUC officers 17 years ago.

This inquiry will examine the murders of chief superintendent Harry Breen and superintendent Robert Buchanan after they met with senior gardai in Dundalk in 1989.

- Brian Dowling