''Now we're yet to positively confirm the exact way that that material has found its way into the criminal underworld, but it would appear most likely that at least a corrupt officer has released that information,'' Overland said.

When asked on ABC TV's Lateline whether major operations had been compromised, he said it was possible but there was no evidence yet of that. Agencies that relied on the squad, including the Australian Federal Police, Customs and the Australian Crime Commission, had not seen any work compromised. Still, they are not impressed and have let Victoria Police know it.

''Well, I'd make the point, we're pretty cranky too,'' Overland said.

''This is obviously not a good situation for us to be in. I'd make the point that I think the vast majority of our staff at the state surveillance unit are personally devastated by this.''

The squad is responsible for phone taps, listening devices and physically observing suspects, work that was crucial in ending the gangland war, bringing down the cell of convicted Melbourne terrorist leader Abdul Nacer Benbrika, large drug importations and a number of anti-corruption investigations many of which involve federal and interstate co-operation. The revelations are sure to test the relationships.

Monash University associate professor Colleen Lewis says there is a pattern of failure in the force's handling of sensitive information, and believes only the disinfectant of a royal commission would end systemic problems.

Stressing this was not a criticism of the Office of Police Integrity, usually charged with overseeing the force, she says that in many of its investigations it works with the police. Lewis said the office had done good work rooting out corruption, but the time had come for more action.

''You never know what the outcome of a royal commission is going to be. The reason I'm advocating a royal commission is because it operates a little bit like a bolt of lightning,'' she says.

''It opens an organisation up in this case it would be that part of the organisation that is dealing with information and the security of that information.''

While outsiders may view the string of corruption cases as evidence Victoria had replaced NSW and Queensland as the home of grubby coppers, the watchdog, police command and Government have repeatedly said the vast majority of police officers are honest and diligent. There are concerns about training and culture, and the latest OPI annual report expressed concern about a sluggishness in updating information management systems and IT.

In this, Victoria Police management has long had form. In the past decade there have been a series of scandals involving the current system, called LEAP, which have ranged from embarrassing mishaps to sinister, politically motivated leaks. LEAP was supposed to be replaced years ago, and delays are ongoing.

Lewis says police command has already been given ample time to overhaul the systems for accessing sensitive information, and she is surprised it has not received higher priority. However, she believed the force's leadership was keen to correct the problems as it was a consistent source of embarrassment.

Along with the outdated technology, there are flaws in people who use and abuse the system for their own purposes.

Apart from hurting the force's image, the scandal has damaged the reputation of the surveillance squad, at least in the public eye. Whether other agencies become more reluctant to share information or other parts of the force would be guarded remains to be seen, however Lewis suspects its standing will suffer.

Even if Overland is right and this is the action of a rogue officer, systemic problems will take longer to redress, and probably years will pass before the squad's information management and reputation is restored to national standard.

''[The latest leak has] undermined the trust that other agencies need to have with anybody that they are working with in a joint operation,'' Lewis says.

''It's unfortunate but I think it will take time for them to rebuild that trust.

''But the leaks in terms of sensitive information in Victoria Police has been going on for years and each time there is a problem, we are sort of led to believe that this is an isolated incident.''

The thought of a royal commission is not one top brass or the Government is willing to entertain. Nixon threatened to resign shortly after getting the job when the idea was floated to probe the gangland killings, having seen first-hand the effect of the Wood Royal Commission in NSW.

Critics allege the continued reluctance implies there is something to hide. There is also suspicion that this week's story was orchestrated, with the police union's secretary-designate Greg Davies reported as saying The Age's revelations on Tuesday were part of a ruse to push for reforms to the Police Regulation Act. Overland's comments on Lateline and 3AW that the police were keen for the bill to pass state Parliament would have done nothing to ease his fears.

Seen as conspiracy theorists by some in command, the police union has genuine reasons to be concerned about the scandal, the bill before Parliament, and the continual damage to the force's reputation through the series of corruption cases. They do not believe their 11,000 members, representing most of the organisation's sworn police, deserve to be tarnished by the acts of a minority.

But onlookers don't expect the state's corruption scandals to end any time soon.

Michael Ruffles is Melbourne Correspondent.