By Miklos Bolza in Sydney

Notorious wife-killer Chris Dawson has challenged a guilty verdict for sexual activity with one of his teenage students after losing a bid to appeal his murder verdict.

The 76-year-old was convicted at Sydney’s Downing Centre District Court in June 2023 of a historical charge of carnal knowledge as a teacher of a girl older than 10 and younger than 17.

His total sentence for the charge was mostly subsumed into his full 24-year sentence for murdering his wife Lynette Dawson in January 1982, merely adding one year to his non-parole period.

His first possible release date will be in August 2041, when he will be 93.

Dawson’s carnal knowledge challenge came briefly before the NSW Court of Criminal Appeal on Thursday and a two-hour hearing was scheduled for late-March.

Only the conviction would be challenged as the sentence was “really no issue”, his Legal Aid lawyer Julian Stevens told the court.

“The verdict of guilty was unreasonable,” the 76-year-old said in a notice of appeal.

Prominent barrister Stephen Odgers SC will represent Dawson in the appeal.

In handing down the verdict, Judge Sarah Huggett failed to take into account evidence of when precisely Dawson had sex with the teen student, the appeal documents said.

In the trial, the former PE teacher admitted having sexual intercourse with the girl but said he only did so after she reached her 17th birthday.

Judge Huggett erred by assuming questions asked in cross-examination of prosecution witnesses indicated the defence case and wrongly applied the burden of proof, the documents said.

The student, who cannot be legally named, was Dawson’s motivation for murdering his wife and disposing of her body after he had become infatuated with the girl, the NSW Supreme Court found in August 2022 after a judge-alone murder trial.

His appeal of the murder conviction was thrown out in June.