As well as exposing the big players in property scams, the Mahon Report revealed just how cheaply councillors could be bought.
Unscrupulous developers, through their 'bagman' lobbyist Frank Dunlop, often had to pay politicians as little as £1,000 to guarantee the green light for their highly lucrative projects.
Sometimes just hosting them at a lavish lunch in one of Dublin's better restaurants was enough to secure their vote.
The ease with which it was possible to corrupt councillors was thrown into sharp relief this week when the Conservative Party treasurer, Peter Cruddas, was filmed in London offering potential donors private dinners with David Cameron -- for £250,000 (€300,000).
Cruddas was forced to resign and the revelations have caused major embarrassment to Cameron.
But here, as the Mahon Report makes abundantly clear, councillors from all political hues were happy to take a small fraction of the enormous profits that unethical developers would make on land they voted to rezone.
"While the potential financial gain was immeasurable," according to Justice Alan Mahon, "the outlay necessary to achieve the rezoning of land in question was, in most instances, relatively modest, often involving sums of £1,000 or £2,000 being paid to a handful of councillors."
The culture of low pay for high returns was evident in several of the cases investigated by the tribunal, including that of the Drumnigh development in Portmarnock, north Dublin.
The owner of the land, car dealer Denis Mahony, employed the services of Dunlop in March 1993 to help get his substantial holding rezoned for residential use.
According to Dunlop, Mahony -- whom he met in the Shelbourne Hotel -- promised to pay him £10,000 in cash, allegedly telling the lobbyist that he "knew how the world worked".
Although he wouldn't receive the cash from Mahony for 13 days, Dunlop put his legendary powers of persuasion to use straight away. The rezoning of the land was passed by 28 votes to 11.
Ten years later, giving evidence at the Mahon Tribunal, Dunlop explained how he used Mahony's money.
A chunk of it was distributed to four Fianna Fail councillors including then senator GV Wright, who was paid £2,000, and Sean Gilbride, who also received £2,000. Further payments of £1,000 each were given to Cyril Gallagher and John Larkin, both now deceased.
Dunlop claims that he handed over the cash in an envelope, wrapped in a newspaper, to Wright in the visitors' bar at Leinster House.
It had been Wright -- who knew Mahony personally -- who had encouraged the car salesman to avail of Dunlop's services. Dunlop would later get a £2,000 "success fee" from Mahony.
In 1993, Denis Mahony was an elder statesman in the Irish motor industry, a legendary salesman who had established his car dealership in 1963.
Mahony had come to prominence in the 1950s when he played Gaelic football for Dublin, but he would truly shine as an entrepreneur.
His name still adorns two large Dublin dealerships and, for generations of well-to-do people, his business has been the go-to place for new Mercedes, Toyota and Lexus cars.
Part of his success was because he hired the best staff. One of his early employees, Joe Duffy, would also go on to change the face of Irish motor retailing when he became the country's first BMW main dealer in 1972.
By 1981, when Mahony purchased the 30-acre Drumnigh land at Portmarnock -- not far from his home in Malahide -- he was a wealthy man.
The £191,000 he paid for the site would not have stretched him unduly. When one considers its position in one of north Dublin's 'des-res' locales, the chances of him making a healthy return on his investment looked guaranteed.
After the rezoning decision of 1993, Mahony faced huge local opposition. More than 2,500 people lodged objections, but the car dealer was willing to wait.
In June 2000, his land was sold for £13.5m to Ballymore Properties. Denis, who was in his early 70s at that stage, had taken a back seat in his business affairs and it was his daughter, Ita, showing some of her father's entrepreneurial know-how, who pushed the sale through.
Ita Slattery and her husband Padraig run one of Dublin's best-known PR firms, Slattery Communications. Their blue-chip clients include Toyota, Lexus and UNICEF, and the company celebrates its 30th anniversary this year.
But Ita Slattery was unwilling to be interviewed for this article. Padraig -- who specialises in "crisis management" PR -- said neither she nor Denis had anything to say on the matter.
"As far as they're concerned, it's history," he told Weekend Review. "Denis, who'll be 85 this year, has co-operated fully with the Mahon Tribunal."
Questions about how the £13.5m was spent, or about the morality of paying Frank Dunlop to secure council votes, remain unanswered.
Today, Denis Mahony's 30-acre site is an exclusive gated estate known as Drumnigh Wood. The houses -- many of them five-bedroom mansions exceeding 5,000 sq ft -- have attracted a super-wealthy clientele and the odd celebrity: Westlife's Brian McFadden and his ex-wife Kerry Katona used to live there.
Access to the estate is restricted -- the development is protected by security personnel 24/7. Several of the houses are on the market with prices up to €1.8m sought.
The Mahon Tribunal exonerated accountant Noel Fox, who had been part owner of some of the Drumnigh land, finding that he did "not contribute to Mr Dunlop's payment nor did Mr Mahony request him to do so nor did he inform him as to any detail relating to the payment. On the balance of probability, the tribunal was satisfied that Mr Fox was unaware of and was not privy to any intention on the part of Mr Dunlop to pay money to councillors in the course of his retention as a lobbyist for the Fox and Mahony lands".
It was a different story in the case of Mahony: "Although in Mr Mahony's case the tribunal did not find that he was aware of Mr Dunlop's intention to pay councillors for their support, it did believe, particularly having regard to Mr Dunlop's request for the IR£10,000 to be paid in cash (as it was), that Mr Mahony must have been at least suspicious that Mr Dunlop might use a portion of the funds in such a manner."
Former Green Party leader Trevor Sargent lives quite close to Drumnigh Wood and is familiar with the Mahony saga. He sat on Dublin County Council when the vote was taken.
Sargent had raised the issue of payments to councillors in 1993 -- the very year that the Drumnigh land was rezoned.
Keen to demonstrate how payments for rezoning were rife in county councils nationwide, he waved a cheque he had received from a developer at a council meeting. Remarkably, Sargent was physically assaulted by other councillors in the chamber.
"What I said caused real anger," he said this week. "Councillors from Fine Gael and Fianna Fail went for me. One of them put me in a headlock in an attempt to grab the cheque.
"In retrospect, I think they were petrified that the cheque had Frank Dunlop's name on it and serious questions would be asked."
The "small-time developer" -- Sargent's words -- apparently hoped the money would induce the Green councillor to read the accompanying letter.
"For €100, these people hoped you would read their correspondence," Sargent says. "For €1,000, they were after your vote. It was multiples of that if they wanted more votes.
"The whole thing cheapened Irish politics and today thousands of people living in developments that should not have been rezoned have to contend with the consequences of the greed."