Patterson was found guilty in July of killing her mother-in-law, Gail Patterson, father-in-law, Donald Patterson and Gail’s sister, Heather Wilkinson, in a case that has been globally followed and dubbed the Leongatha mushroom murders.

A jury also found the 50-year-old guilty of the attempted murder of Ian Wilkinson, Heather’s husband, who survived the 2023 meal at Patterson’s home in Leongatha, a town of about 6,000 people, some 135 km (84 miles) southeast of Melbourne.

Justice Christopher Beale said the substantial planning of the murders and Patterson’s lack of remorse meant her sentence should be lengthy.

“The devastating impact of your crimes is not limited to your direct victims. Your crimes have harmed a great many people,” he said at the sentencing hearing at the Supreme Court of Victoria in Melbourne.

“Not only did you cut short three lives and cause lasting damage to Ian Wilkinson’s health, thereby devastating the extended Patterson and Wilkinson families, you inflicted untold suffering on your own children, whom you robbed of their beloved grandparents.”

Ian Wilkinson thanked the police and prosecutors who brought Patterson to justice, as well as medical teams that treated him and the other victims.

“We’re thankful that when things go wrong, there are good people and services and systems available to help us recover,” he said outside the court.

At a pre-sentencing hearing last month, Patterson’s barrister Colin Mandy urged Beale to impose a non-parole period on the sentence, meaning she would have the possibility of eventual release, as her “notorious” reputation would make prison more onerous for her than the average offender.

A corrections officer previously told the court Patterson was being kept in isolation for her own safety, and was permitted contact with only one other prisoner who is in jail for terrorism offences.

In his sentencing remarks, Beale said he had taken Patterson’s isolation into account.

“You have effectively been held in continuous solitary confinement for the last 15 months, and at the very least there is a substantial chance that for your protection you will continue to be held in solitary confinement for years to come,” Beale said.

Including time already served, Patterson will have just turned 82 before she can be considered for release.

The prosecution argued Patterson should never be released.

Patterson, who maintained her innocence throughout the trial and said the poisonings were accidental, has 28 days to appeal her sentence. She has not indicated whether she will do so.

Patterson’s non-parole period of 33 years is the longest ever for a woman convicted of murder in Victoria.

Only one woman in Australia has ever received a life sentence without the possibility of parole.

Australia does not have the death penalty.

The deaths devastated the close-knit rural community of Korumburra, where all the victims lived.

The court received a total of 28 victim impact statements, of which seven were read publicly at last month’s hearings.

Ian Wilkinson, a pastor at a local church and the sole surviving guest of the lunch, told last month’s hearing that the death of his wife had left him bereft.

“It’s a truly horrible thought to live with that somebody could decide to take her life. I only feel half alive without her,” he said, breaking down in tears as he delivered his victim impact statement.

The extraordinary media interest in the case, which gripped Australia for much of the 10-week trial, had been traumatic for the family, Erin Patterson’s estranged husband Simon Patterson – who was invited to the lunch but declined – said at the same hearing.

Journalists and television crews from around the world descended on the town of Morwell when the trial began in April, with millions of Australians following proceedings live through one of several popular daily podcasts.

For the first time in its history, the Supreme Court on Monday allowed a television camera into the court to broadcast Beale’s sentencing remarks live due to overwhelming public interest.

The trial has already inspired several books, documentaries, and a drama series, “Toxic”, set to air on state broadcaster ABC.