West Coast chief executive Trevor Nisbett and other club officials oversaw a six-year culture of cover-up that ignored illicit drug use by star players and allowed serious misconduct and criminal activity to flourish, a secret report into the club reveals.

Written in 2008 by retired Supreme Court judge William Gillard, the damning document had been kept under wraps by the AFL until its publication in an Eastern States newspaper yesterday.

Mr Gillard’s three-month investigation into West Coast concluded the club had shut its eyes to “the obvious” and allowed the “seeds of the culture” to start growing as far back as 2002, when evidence of drug taking emerged.

“It is inconceivable that the senior members of the administration of the club were not aware of the reports,” Mr Gillard wrote.

“I have no doubt that in the year 2002 the culture was to minimise the fallout and treat the players leniently.”

Because of the club’s inaction on illicit drug taking, Mr Gillard was convinced former West Coast captain Ben Cousins slid into drug addiction, where he remains.

He said the Eagles had not properly penalised players at the earliest opportunities and “as a result the culture flourished”. He believed then coach John Worsfold also could have done more to pull Cousins and others into line after being told in 2002 of drug use.

“The Cousins saga amply demonstrates and exemplifies the dangers in failing to respond to a problem early and nipping it in the bud,” he said.

“The sore festers and every effort is made to cover it up without confronting the real cause and seeking to eradicate it.”

But Mr Gillard’s 87-page report, which was ordered by the AFL in late 2007 after the sacking of Cousins from the club and ongoing misconduct by other West Coast players, was stamped “not to be released or published unless authorised by a resolution of the AFL Commission”.

The AFL would not comment on the leaking of the report yesterday and West Coast said there was nothing in the report that it wasn’t aware of 10 years ago.

Worsfold, now coaching Essendon, hit back at calls yesterday for the 2006 premiership to be stripped from the club.

“I’m sure at any workplace in the country if you quizzed your staff on a question on whether they’ve ever used illicit drugs, I know the answer you’re probably going to get,” he said. “Then it’s up to every individual as to how much faith they put in that.”

He disputed that he and other Eagles officials ignored evidence of misconduct, saying: “I still think that I dealt with the things as they were presented to me ... when somebody implies something, but with absolutely no evidence other than they think something — I really do still battle to say ‘How do you act on that?’”

Mr Gillard spoke to 47 witnesses and concluded some players and officials lied to him during the inquiry.

“The culture could be described as the view held by players and the club, that if they were successful on the field what they did outside the club was of little consequence,” Mr Gillard wrote.

“If trouble resulted the club would take steps to minimise the gravity of the misconduct and impose a fairly lenient sanction.”

He said the club would go into “damage control” to “defuse the situation in the media”.

The investigation looked at the connection between players such as Cousins and Michael Gardiner to then organised crime target John Kizon, evidence that police warned a club official about players taking drugs, punch-ups between drunken players and Chad Fletcher’s collapse in Las Vegas in 2006.

Despite all the evidence of drug use against Fletcher, he wasn’t penalised by the club.

“The culture appears to have gone that far,” Mr Gillard wrote. “Some players were of the view they could do what they liked.”

Mr Gillard said the club accepted it was in crisis after the Fletcher incident and made significant changes around its culture.

Former Eagles captain Chris Judd said the Cousins story remained a tragic one, but the education programs changed most players for the better.