Sydney doctor Brian Kenneth Crickitt gave wife fatal insulin dose to be with lover

Dr Brian Kenneth Crickitt arrives at the Supreme Court in Sydney last year. Photo / AAP

A Sydney doctor has been jailed for at least 20 years and three months for murdering his second wife with a lethal dose of insulin.

Brian Kenneth Crickitt, 63, was found guilty in December of murdering wife Christine in their Woodbine home in Sydney's southwest on New Year's Eve, or early New Year's Day in 2010, the Daily Mail reported.

Crickitt gave no visible reaction after Justice Clifton Hoeben handed down the maximum 27-year sentence on Friday.

Linda Livermore, centre, walks with family members after giving evidence in the murder trial of Dr Brian Crickitt last year. Photo / AAP

But the victim's brother David called out "hear hear judge", while people around him clapped.

The judge found Crickitt tricked his wife into being injected in the buttock with insulin for health reasons, despite not being a diabetic.

He used a lethal dose of fast-acting insulin after becoming fed up with his marriage and besotted with his new lover, Linda Livermore.

Justice Hoeben said a breach of trust was involved because Crickitt was both the victim's husband and treating doctor.

"The deceased was left to die a painful death alone by someone whom she trusted to care for her," he said.

"The offender's motivation to murder his wife was essentially based on self-interest and what he perceived would make his life better in the future."

The judge referred to the need for a strong element of "general deterrence" in delivering the sentence.

"The abuse of trust which characterised this offence is not to be tolerated in our community," he said.

"Medical professionals and doctors, such as the offender, who misuse the trust placed in them by those to whom they provide treatment and care by committing serious criminal acts against them, should know that they will be held accountable and will be met with heavy punishment."

During the sentence hearing in March, the victim's daughter Tracey Wiggins told the court she was forced to meet her stepfather's mistress the day she found out her mother died.

Dr Brian Kenneth Crickitt, centre, arrives with new wife Julie Crickitt, right, to the Supreme Court in Sydney last year. Photo / AAP

Ms Wiggins said - in a statement read by her husband - that she felt nauseated when she saw Ms Livermore drive her dead mother's car to the morgue in a "heartless" act.

"The deception and the betrayal is incredibly debilitating," she told the court.

Ms Wiggins said she felt guilty about the murder because she knew their marriage was troubled and her mother was worried by Crickitt's strange behaviour.

"What a deplorable ... waste of my lovely mother's life," she said in the statement.

"My mother's death broke my heart."

Defence barrister Tim Gartelmann SC told the court there was evidence the doctor suffered mental health problems for decades and may have a tougher time than most in jail due to his age.

Crown prosecutor Mark Tedeschi SC said the crime constituted a serious betrayal of trust because Crickitt was not only his wife's partner, but also her general practitioner.

He said Crickitt would have known his wife would die relatively slowly and that he killed her around New Year's Day because he knew the autopsy would be delayed.

Crickitt - who has since married a third wife Julie - will be a nonagenerian when he is eligible for parole in 2037.