By Tara Cosoleto in Melbourne

After losing her bid for a retrial, mushroom murderer Erin Patterson could take her fight to the highest court in Australia. But her prospects of success are far from rosy, a legal expert says.

Patterson will wake up at the Dame Phyllis Frost Centre on Saturday knowing she is unlikely to see beyond the four walls of the prison ever again.

Her appeal against her murder and attempted murder convictions failed on Friday as the Victorian Court of Appeal instead increased her sentence to life without parole, in line with a prosecution appeal.

Her offending was so shocking, the court said her 33-year non-parole period was inappropriate.

Removing a parole period was a rare move for an appeal court, criminology and justice expert Brianna Chesser said.

“It really speaks to the gravity of the offending,” the RMIT associate professor told AAP.

“I was expecting the non-parole period to be raised, maybe to 37 years.

“But to remove it altogether was definitely a shock.”

Patterson will have 28 days to lodge an application for special leave to appeal to the High Court of Australia.

If she is granted special leave, she will then have a formal appeal hearing.

But 90 per cent of cases didn’t even cross that first special leave hurdle, Ms Chesser said.

The Victorian court’s dismissal did not automatically give Patterson the right to challenge in the High Court, Ms Chesser said.

“The court only deals with cases that shape national law,” she said.

“This case would be of particular importance because of the fact that it’s high profile.

“But you’d be looking for some sort of egregious procedural irregularity, some sort of human rights violation – something really serious.”

Ms Chesser does not believe Patterson’s case falls into any of the categories the High Court usually considers.

But she still expects the convicted killer to try.

“It would make sense that she’d run it to the very end and exhaust all possible avenues,” Ms Chesser said.

Patterson deliberately served deadly beef Wellingtons to her former in-laws Don and Gail Patterson, 70, and Gail’s sister Heather Wilkinson, 66, in July 2023.

The three guests died after the meal at Patterson’s Leongatha home, in regional Victoria, while Heather’s husband Ian fell seriously ill but survived.

She fought to quash her convictions, arguing she suffered a substantial miscarriage of justice and she should have a retrial.

“This offending was extraordinarily cold and calculated and stands to be denounced in the strongest terms,” the Court of Appeal judges said on Friday.

Patterson is only the second woman in Australia to be sentenced to life behind bars without parole.

The first was NSW woman Katherine Knight, who was jailed in 2001 after stabbing her de facto husband to death, skinning him and then trying to serve his cooked flesh to his children.

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