"We do our homework and we control the situation. Out on the street anything can happen," he said.

He said the closest he came to serious injury was as a young constable when a man pulled a knife on him on a railway station.

On Tuesday about 3.40am a  31-year-old First Constable was shot in the head attempting to pull over a suspect car, the sort of event that happens hundreds of times a day.

But this was no routine traffic matter. The driver may well have been involved in shooting the front fence of a house in Katandra Crescent, Broadmeadows earlier that morning – the home of George Williams, father of dead gangland killer Carl Williams.

This may also be linked to the fire bombing of a house in Primrose St, Essendon  – just a few doors from the home of Carl's ex-wife, Roberta.

But what is known is the police divisional van followed the suspect Ford Escape into the dead-end Robinson St, Moonee Ponds.

Trapped, the driver of the Escape did exactly that. He did a U-turn in an adjoining school and as he passed the police van fired a shot with a shotgun, shattering the driver's side window and striking the policeman in the back of the head as he instinctively turned away from the blast.

The policeman ducked just as the shot was fired with most of the pellets hitting his headrest. The extent of the damage indicated if the officer had not dodged the impact would have been fatal.

This was no warning or accident. The offender intended to kill.

Police are now discovering guns every two days in cars in Melbourne's north-west and dealing with a drive-by shooting every six days.

In the Frankston area police have also seen a spike in low-level ice dealers now carrying firearms.

Part of it is "gangster chic", where wannabe crooks carry guns as fashion accessories. Another is an underworld arms race where criminals carry guns because their enemies are armed.

Certainly some Middle Eastern crime gangs routinely shoot rivals in the legs as an intimidation tactic.

Senior police say courts should be tougher on offenders carrying guns, where it should be accepted that if they are armed they are prepared to shoot. And it is ridiculously hard to build a case of gun trafficking as you have to prove multiple purchases when logic says one sale is enough.

Not since the 1996 Port Arthur massacre gun amnesty has there been so many firearms freely available in the underworld.

Police are trained through Operation Catch to improve their observation skills in order to identify suspect drivers who may be carrying drugs or firearms.

Although the rate of police being targeted by armed offenders remains low there can be no doubt the risks in law enforcement is on the rise.

In September last year Abdul Numan Haider, 18, lured an Australian Federal Police officer and a Victoria Police member into the Endeavour Hills police station car park with the intention of stabbing them both to death.

He wounded both men but was shot dead before he could complete his mission.

In October last year Sergeant Rob Campbell was shot and badly wounded with his own weapon as he tried to disarm a 150-kilogram knife-wielding offender.

Every hour police are dealing with someone so disturbed or drug-affected that the suspect needs to be hospitalised and recruits in the academy are now being trained with techniques to deal with the profoundly irrational.

And because of the risks of terror attacks, police security has been increased with solo patrols banned, motorbike units to  work in pairs, front-counter police to be armed and uniform police must to wear ballistic vests.

The challenge for new Chief Commissioner Graham Ashton is to protect his workforce without over-reacting.

In the 1980s, after the Russell Street Bombing and Walsh Street, where two police were ambushed and murdered and the wounding of seven police by gunman Pavel Marinof, senior police restructured survival training along the US model.

It resulted in a spike in the number of suspects shot by police and a need to rethink training methods.

Melbourne remains a safe city. Police cannot afford to develop an us-against-them mentality.

And crooks need to know that if they shoot at cops it will end badly.

Police fully expect to solve Tuesday'sshooting. The smart advice to those involved would be to come out with your hands up.