The accused Bourke Street driver will give evidence from the witness box during his trial to explain his “very important reason” for killing six people and injuring dozens more, as James Gargasoulas’ defence barrister concedes he was in a drug-induced psychosis when he ran the pedestrians down.

Mr Gargasoulas’ trial has opened in the Victorian Supreme Court as he fights six murder charges and 27 counts of reckless conduct endangering life for deliberately running over pedestrians in Melbourne’s CBD in January 2017.

The 28-year-old has pleaded not guilty despite agreeing to almost all of the facts of the prosecution’s case, including that he was in a drug-induced psychosis at the time of the rampage.

Defence barrister Theo Alexander told the jury Mr Gargasoulas has a mental illness but neither his mental state now, or his drug-induced psychosis at the time of the tragedy, offered a defence to the charges.

“He says that he had a very important reason, or reasons, for what happened on the 20th of January 2017,” he said.

“Mr Gargasoulas, for better or for worse, is absolutely committed to his explanation and as another jury found, he is fit to stand trial.

“He is accordingly entitled to say what he wishes about the offences with which he’s been charged.”

Dr Alexander said Mr Gargasoulas would give evidence during the week-long trial after the prosecution had closed its case.

Earlier, the court was played CCTV footage of Mr Gargasoulas driving a stolen maroon sedan into the city before performing donuts outside Flinders Street train station as police watched on.

There was an audible gasp as the vision showed the car turn up Bourke Street and onto the footpath where it hit a pedestrian who would become Mr Gargasoulas’ first alleged victim.

The car could be seen accelerating up the footpath along Bourke Street, colliding with more pedestrians.

Some were thrown onto the car’s bonnet before sliding off, while other pedestrians were thrown metres from the car.

Director of Public Prosecutions, Kerri Judd QC, told the jury Mr Gargasoulas appeared to target people as he drove.

“In a period lasting only about a minute, during the busy lunchtime period, the accused left a trail of death and carnage along Bourke Street,” she said.

People pay their respects in the Bourke Street Mall in January 2017. Photo: AAP

Ms Judd told the court Mr Gargasoulas had to swerve a metre to hit a nanny and two children in a pram.

The three-month-old baby, Zachary Matthew-Bryant, was thrown almost 70 metres from the pram and died.

His two-year-old sister, Zara, was also thrown from the pram and fell to the ground still strapped into the pram insert, the court heard.

She suffered serious injuries but survived.

Ms Judd also detailed how the other five victims were killed by the speeding car.

Yosuke Kanno, aged 25, Bhavita Patel, 33, Jess Mudie, 22, Matthew Si, 33, and Thalia Hakin, aged 10, were also killed.

Ms Judd said the series of events that culminated in the Bourke Street tragedy began when Mr Gargasoulas stabbed his brother Angelo with a large kitchen knife, almost killing him.

Mr Gargasoulas fled from his mother’s home at Windsor, in Melbourne’s south-east, shortly after, prompting a police pursuit of Mr Gargasoulas’ until his arrest on Bourke Street when his car suffered a mechanical failure and was rammed by police.

He had been followed by police for 12 hours prior to the alleged attack, and was communicating with a police officer via text message.

Detective Senior-Constable Murray Gentner sent Mr Gargasoulas a text message which simply said “Stop”, just minutes before the rampage.

As Mr Gargasoulas drove in circles outside Flinders Street station, the court heard the police officer yelled at Mr Gargasoulas: “What are you doing? Calm down.”

Ms Judd told the jury Mr Gargasoulas had made several chilling warnings about his plans to kill pedestrians in the hours leading up to the attack.

The court heard he had told one friend:

“I’m going to do something drastic, take everyone out, they can suffer the consequences.

“Watch me, you’ll see me tonight on the news.

“The police have stopped me before, but they ain’t going to get me this time. I’ll make you believe me”.

Hours later he told another friend: “If the cops come find me, I’ll run everyone down in the city.”

The trial before Justice Mark Weinberg and a jury of seven women and six men continues.

-ABC