This week, as former Queensland cabinet minister Gordon Nuttall was spectacularly convicted of corruption, Australia's evolving reverence of "mateship" took one of its dark turns.

So strongly is the concept burned into the national psyche that former Prime Minister John Howard wanted it enshrined in the preamble of the constitution. Other political and community leaders continue to run it out as an embodiment of Australian values.

But in Brisbane District Court the 36 charges successfully laid against Nuttall reminded the nation that mates can sometimes look after each other too well, and to the detriment of those outside the circle.

Australia had seen it before: in Western Australia, for example, where intimate networks of friends and acquaintances created the scandalous WA Inc of the 1980s, linking businessmen and politicians in a corrupt web that eventually sent many of them to jail.

In Queensland it was taken to the extreme by the long, corrupt years of National Party rule that began to unravel when two investigative journalists, Phil Dickie of the Courier-Mail and Chris Masters of the ABC, revealed a system rotten to the core.

Their stories forced the establishment of the Fitzgerald Inquiry, broadened from its initial police focus to embrace systemic corruption riddling politics and the public service.

The inquiry claimed some of the state's biggest scalps: former Police Commissioner Terence Lewis, stripped of a knighthood and jailed, former Premier Joh Bjelke-Petersen acquitted by a hung jury but banished from power and his party decimated, and four ministers jailed.

This month marks the 20th anniversary of the delivery of Tony Fitzgerald QC's report to the Queensland parliament, and new scrutiny of the state in the wake of Nuttall's conviction.

Before Nuttall, former Tourism Minister Merri Rose had been jailed for trying to blackmail her boss, former Premier Peter Beattie, two Labor MPs were imprisoned on child sex charges, and former emergency service minister Pat Purcell narrowly escaped trail for assault charge.

Across Australia, commentators have been asking if life has changed that much in the sunshine state.

But unlike the Bjelke-Petersen's cowboy years, the Nuttall case did not reveal endemic corruption. To the contrary, while embarrassing and in some ways tragic, the charges have been held as proof that the massive cleansing of the system after Fitzgerald has worked.

What it did illustrate were the risks inherent in a relatively small business and political elite, concentrated heavily in a limited range of often interlocking sectors, where helping mates comes naturally. Nuttall's case showed that the lines between networking, unfair advantage and corruption are finely drawn.

Nuttall was a small fish who pushed himself into a large and turbulent pool. He was a latecomer to politics, emerging from a modest, working class background to become a bank accountant ambitious to share in the leapfrogging wealth of Queensland's property sector.

He wanted affluence for himself, and a platform for his children's prosperity.

In the 1980s he became active in the Labor Party, finally winning a seat in Beattie's Government in 1992. Along the way he had become friends with solicitor Bruce McDiarmid, a Labor supporter who was riding the property boom to wealth.

McDiarmid helped Nuttall out with a A$120,000 ($148,840) loan when attempts to cash in the property boom turned sour a decade ago, and later introduced the MP to men of real influence: coalminer Jim Gorman, his solicitor Harold Shand and, after a bizarre twist, mining magnate Ken Talbot, worth about A$750 million.

Nuttall had originally tried to advance out of backbench anonymity by using information he had received from Gorman and Shand to assail Talbot in parliament - a move he came to regret deeply, and was later to overcome with an apology.

Evidence giving during his trial showed that Nuttall was not shy in seeking help from his mates. He asked for money, and received it: Shand advanced A$60,000 to help cover interest on a A$1 million loan, and Talbot provided A$300,000 in monthly instalments.

Shand and Talbot have yet to stand trial.

Nuttall's career, meanwhile, was going downhill. Premier Anna Bligh, then Beattie's deputy, had been forced to co-sponsor a motion to protect him from parliamentary allegations of perjury.

In 2005 he was forced to step down as health minister by the scandal surrounding Indian-born doctor Jayan Patel, known as "Dr Death" for his alleged involvement in a series of patient deaths at Bundaberg Hospital, and who was extradited from the United States to stand trial.

Nuttall appeared to be genuinely stunned when he was first charged, then convicted, of receiving secret commissions from Shand and Talbot, and the news that the state's Crime and Misconduct Commission had recommended further charges of corruptly receiving more than A$180,000 from a developer involved in a major waste-water project.

Nuttall believed that this was what mates did for one another. He needed help to secure a future for himself and his family, and his mates were happy to help out. "Nothing was asked, nothing was given," he said in court. "For me, it was nothing more than an act of kindness."

Just before his conviction, Nuttall told The Australian: "I didn't do anything wrong, that's my honest belief, because all I was doing was trying to set up my family for the future.

"They have turned a good and kind deed into something dirty and nasty, just to suit their egos and justify their existence."

Prosecutor Ross Martin ridiculed the thought, telling the court that Nuttall's crime was worse even than that of former New South Wales prisons minister Rex Jackson, who spent seven and a half years in jail for accepting bribes to release prisoners.

Martin said Nuttall had compromised others by brazenly drawing them into a scheme motivated by greed to increase the family's wealth, and marked by "a lack of fear of capture and an utter lack of remorse".

Chief Judge Patsy Wolfe yesterday sentenced Nuttall to seven years' jail.

State shadow attorney-general Lawrence Springborg used Nuttall's conviction to try to taint Labor with the shadow of Fitzgerald, claiming it marked a "serious trail of misconduct and corruption".

But most commentators agree that while flaws and risks remain, Queensland is no longer the rogue state of the Bjelke-Petersen years.

The Fitzgerald Inquiry led to a series of laws and reforms, and the eventual creation of the Crime and Misconduct Commission, whose wide powers include the inversion of the onus of proof: defendants must prove themselves innocent.

The commission closely monitors the police and the impact of their powers, and probes allegations of misconduct within the state public service, recently concluding an investigation into nine agencies that produced recommendations to tighten controls.

Even so, commission chairman Robert Needham has warned that while corruption was not endemic in Queensland, scandals in local government had shown that standards had noticeably slipped and that complacency was a real threat.

"Twenty years ago when Tony Fitzgerald handed down his recommendations, the need to fight corruption was fresh in the minds of most people around Australia," he told the publication Government News. "However, there is a very real risk that that memory has faded."

* Disgraced Queenslander Gordon Nuttall was jailed for seven years for accepting secret commissions from two wealthy businessmen.
* Former Queensland Tourism Minister Merri Rose spent three months behind bars for trying to blackmail her boss, Premier Peter Beattie, to give her a job.
* Veteran state Labor MP Bill D'Arcy spent seven years of an 11-year term behind bars for child sex offences.