“A deliberate full-frontal collision with Gargasoulas’ vehicle as he proceeded along Swanston Street was the only real option left for police to stop him from this point onwards.”

The report also shows that Victoria Police’s vehicle pursuit policy at the time of the incident was a mess of sometimes contradictory instructions and inflexible regulations that were interpreted differently by command and uniform officers.

“This was demonstrated at various times in events leading up to the Bourke Street tragedy where dynamic and decisive decision making was stifled at critical times, creating an opportunity for Gargasoulas to avoid apprehension,” Mr Fontana wrote.

“Police members were not prepared to take a risk in what they perceived to be a breach of policy due to fear of repercussions and lack of confidence in their management to support them.”

Mr Fontana also criticised the decision by supervisors of the police's Critical Incident Response Team to refuse a request to help “box-in” Gargasoulas when he was believed to be parked in St Kilda, then Elsternwick, in early morning hours before the incident.

“CIRT response vehicles are not designed for pursuits or high risk mobile intercepts and … this means that they should not be used for pursuits. However, in hindsight there was no reason why the CIRT could not have deployed to the area to assist in a search for Gargasoulas or the stolen vehicle that he was driving.”

Officers from the Port Phillip Crime Investigation Unit are heavily criticised for their failure to arrest Gargasoulas after he committed a series of escalating offences, including stabbing his brother, in the lead-up to his vehicle attack.

About two hours before his stolen red Commodore reached the CBD, two officers were ordered to terminate a pursuit of Gargasoulas after following him across several suburbs to Moray Street in South Melbourne.

The report found that the failed pursuit should have signalled that it was “time to regroup” and review the planned operation, including the level of command and control and operational support needed to safely arrest Gargasoulas.

“This did not happen and I am of the view that this is a failing of Port Phillip CIU management,” Mr Fontana wrote.

“In my view, what should have been a well-planned operation to resolve this evolving situation, unwittingly turned into a poorly coordinated, unplanned response.”

Despite knowing Gargasoulas’ criminal history and being in contact with him by text message asking him to surrender, the report lambasted Port Phillip officers for failing to share critical information with other units, including the air wing.

“In fact, Port Phillip CIU on air communication with operational units was almost non-existent – their silence was deafening,” Mr Fontana wrote.

Detective Sergeant Adam Vohmann, the officer who nominated himself as the incident controller of the operation to stop Gargasoulas, was “ill-prepared” to be in charge because he was at another crime scene, the report found.

“In fact, other than issuing a few initial instructions before directing units to change channels, he effectively exercised no control of the ongoing pursuit,” Mr Fontana wrote.

The Critical Incident Review was launched by Mr Fontana in February 2017 and involved assessing the actions of police in the lead-up to the massacre.

The report, later released to the coroner, details blow by blow criticisms of numerous police officers involved in Gargasoulas’ failed arrest and how they handled the incident.

This includes criticisms that police actions were poorly coordinated and unplanned.

Chief Commissioner Graham Ashton had sought to prevent the public airing of Mr Fontana’s report into police handling of the nine-hour hunt for Gargasoulas.

But the families of those killed, along with media organisations including The Age, fought the force's attempt to keep that report secret because it was ‘‘inextricably linked and inextricably intertwined’’ with attempts to understand events leading up to the massacre.

It enabled the internal review to be referred to in full during the inquest.