The former rugby league star and teacher will soon learn whether his conviction for murdering his wife Lynette will be overturned when the Court of Criminal Appeal hands down its judgment.

Dawson was jailed in August 2022 for the murder of his wife Lynette Simms, who vanished without a trace from their Bayview home on Sydney’s northern beaches in January 1982.

The 75-year-old appealed to the state’s highest court, the Court of Criminal Appeal, earlier this year.

Justices Julie Ward, Anthony Payne and Christine Adamson, who oversaw his three-day appeal hearing in May, will on Thursday afternoon hand down their judgment.

In the days after Lynette Simms vanished, Dawson moved his teenage lover – a former student and the family’s babysitter – into his Gilwinga Drive address.

Nearly two years ago, Supreme Court Justice Ian Harrison found Dawson killed his wife to have “unfettered access” to the young woman, JC.

He was sentenced to 24 years in prison, with an 18-year non-parole period.

Lynette Simms was last seen on Friday, January 8, 1982 when she spoke to her mother on the phone.

According to Dawson’s version of events, given to detectives during his only police interview in Queensland in January 1991, Mr Dawson claimed he dropped off his wife at a Mona Vale bus stop early on the morning of Saturday January 9.

Dawson told detectives she had failed to meet him at the Northbridge Baths, where he worked as a lifeguard.

He had claimed he received a long-distance phone call from Lynette during his shift saying she needed time away and had several further phone calls with her in the ensuing days before she told him she would not be returning to their home.

Crown prosecutors during his 2022 trial, and appeal earlier this year, relied on the fact that Ms Simms never had any contact with any person after January 8, 1982, including her family, friends, colleagues and children.

Dawson appealed his verdict on five grounds, including that he suffered a “significant forensic disadvantage” due to being unable to call evidence or witnesses due to the extraordinary delay between Lynette’s disappearance and the start of his trial in May 2022.

They also argued it could not be proven that Dawson did not receive a phone call from Lynette the afternoon he was working at the Northbridge Baths.

Phillip Day, a Dawson family friend who was present at the Northbridge Baths that afternoon, was unable to be called because he died before the trial began.

Dawson’s barrister, public defender Belinda Rigg SC told the Court of Appeal hearing earlier this year that there was nothing “sinister” about Mr Day’s presence at the pool.

Ms Rigg also argued that other pieces of evidence had been lost to time – including phone records and Ms Simms’ bank statements – which could have proven she was alive after January 9.

The court heard that in the months leading up to her disappearance, Dawson had made attempts to leave Lynette, including just before Christmas 1981 when he attempted to move to Queensland with JC and start a new life.

The court heard that JC and Dawson did not make it to Queensland after she became ill and asked that he turn the car around.

The Court of Appeal will hand down its judgment on Thursday afternoon at 2pm.