Nearly 41 years after he murdered his wife Lynette so he could be with a teenage former student, ex-teacher and rugby league star Chris Dawson has been sentenced to 24 years in jail.

On Friday afternoon, 14,938 days after his wife went missing from their Sydney northern beaches home, Dawson stood in Sydney’s Supreme Court wearing prison greens as he was sentenced by Justice Ian Harrison.

Dawson pleaded not guilty to the murder of his wife who vanished from their Bayview home in January 1982 and over the past four decades has consistently maintained his innocence.

He was on Friday sentenced to 24 years in jail with an 18-year non-parole period, meaning Dawson will first be eligible for parole in August 2040.

“The unavoidable prospect is that Mr Dawson will likely die in jail,” Justice Harrison said.

His lawyers have already lodged an intention to appeal the guilty verdict.

After a long-running trial earlier this year, Dawson was in August found guilty of the murder, after Justice Harrison said the only explanation was that he killed his 33-year-old wife to be with one of his former students.

Chris Dawson was earlier this year found guilty of his wife’s murder. Photo / NCA Newswire / Gaye Gerard

He was found to have killed his wife just weeks after he had unsuccessfully attempted to run off with the teenage babysitter to start a new life in Queensland.

• The teacher, the wife, the babysitter and the 40-year wait - what happened to Lynette Dawson?
• Chris Dawson's estranged daughter publicly speaks about murder case

Lynette Dawson was last seen on Friday, January 8, 1982, with her last known contact with another person a phone call to her mother Helena Simms.

Her body has never been found and Justice Harrison found there was no “reasonable possibility” she voluntarily left and never contacted her friends or family, including her two children.

Lynette Dawson’s family, including her brother Greg Simms, have pleaded with Dawson to reveal where she is buried.

During a heart-wrenching victim impact statement delivered during a sentencing hearing earlier this year, Lynette Dawson’s daughter Shanelle Dawson said: “Please tell us where she is. You had no right, you are not a god.”

During a police interview in 1991, Dawson told detectives he had dropped off his wife at a Mona Vale bus stop so she could go shopping and it was planned that she would meet him later that afternoon.

She never arrived at the Northbridge Baths, where Dawson worked as a part-time lifeguard.

Dawson had claimed that his wife phoned him at the baths to say she needed time away, and phoned him on several more occasions before finally saying that she would not be returning.

But Justice Harrison found Dawson’s “infatuation” and “obsession” with the schoolgirl, who can only be known as JC, led him to murder his wife.

JC became the couple’s live-in babysitter in 1981, and during the trial told the court she would have sex with Dawson while his wife was asleep.

She was eventually forced to move in with Dawson’s brother Paul, who lived several doors up on Gilwinga Drive after she was confronted by Lynette Dawson, the court heard.

In late 1981, Dawson and JC packed his car full of their clothes and belongings and set out to Queensland to start a new life.

JC was the prosecution’s star witness during his trial. Photo / NCA NewsWire / Damian Shaw

But JC forced Dawson to turn the car around before the border after she grew ill and told him that she missed her family.

In early 1982, JC travelled to South West Rocks to holiday with her friends and family.

She said that during her stay she received a phone call from Dawson who told her: “Lyn’s gone, she’s not coming back.”

Judge Harrison said in his judgment on Friday: “JC was beyond Mr Dawson’s physical reach and control and beyond his emotional sway.

“She was instead in the company of other young women and significantly young men of her age.”

JC went on to marry Dawson, however she gave a statement to the police after they separated in 1990.

Justice Harrison found Dawson was so “distressed”, “frustrated” and “tortured” by JC’s absence that he “resolved” to kill his wife.

He said that Dawson was driven by a “possessive infatuation” after JC had expressed her desire to end their relationship.

In handing down his sentence, Justice Harrison said he was satisfied that Lynette Dawson was killed at her home on 2 Gilwinga Drive, despite the fact her body has never been found.

He described Dawson killing his wife for “selfish and cynical reasons” and treating his wife as “completely dispensable”.

Chris and Lynette Dawson. Photo / Supplied

Justice Harrison said Lynette Dawson was “faultless” and “completely unsuspecting” despite the decline in their marriage in the months prior.

Dawson’s lawyers have already filed a Notice of Intention to Appeal.

His solicitor Greg Walsh has previously said he would be represented by Senior Public Defender Belinda Rigg, SC in the Court of Criminal Appeal.

Barrister Pauline David, who represented Dawson during his trial, has been appointed as a District Court Judge.

- Steve Zemek and Lauren Ferri, news.com.au