The Disclosures Tribunal — investigating complaints about the alleged treatment of Garda whistleblowers — has cost taxpayers more than €5.1m to date.
Almost €2.8m of that sum has been paid to lawyers working for the inquiry, with two barristers on course to become tribunal millionaires.
A further €1.4m has been spent on salaries and wages for tribunal staff.
But the figures are set to be dwarfed in the coming months as the tribunal begins paying third-party legal costs in respect of witnesses who have appeared since it began in 2017.
The top earner so far is tribunal counsel Patrick Marrinan SC, who was paid €939,887 between March 2017 and November 2019. His colleague, Diarmaid McGuinness SC, has earned €926,443.
Tribunal barristers Kathleen Leader and Sinéad McGrath have earned €385,009 and €188,495 respectively, while documentary counsel Emma Toal and Lalita Morgan Pillay have been paid €192,050 and €140,712 respectively.
The figures, released to the Irish Independent under the Freedom of Information Act, showed other costs included €230,455 on stenography and transcripts, €84,515 on IT, €23,576 on office supplies and €1,461 on taxis.
The tribunal has produced three interim reports so far and examined allegations made by former Sergeant Maurice McCabe and Garda Keith Harrison.
It found Sgt McCabe, who raised concerns over penalty points abuses and other policing matters, was the victim of a «campaign of calumny» waged by former Garda Commissioner Martin Callinan.
However, it rejected allegations by Gda Harrison and his partner Marisa Simms that gardaí colluded with Tusla to coerce a statement from her and directed social workers to visit their family home.
The tribunal is currently engaged in a second module which is considering complaints from other gardaí. Hearings relating to the alleged treatment of Garda Nick Keogh, who claims he was targeted after raising concerns about alleged Garda collusion with drug dealers, began last October and are due to resume again on Monday following a six-week break.
The tribunal is also considering complaints from other members of the force, but it is unclear at this stage if there will be further hearings after the Keogh section is finished.
It was expected to examine further claims by Gda Harrison he was subjected to a five-year campaign of intimidation after arresting a colleague for drink driving.
However, although he has not retracted his allegations, Gda Harrison recently withdrew from the tribunal, saying he had lost confidence in the process and wanted it to desist from further investigating his treatment in the force.