A gay mathematician's convicted murderer is trying to recall his on-the-fly guilty plea in a "uniquely unusual" case, after claiming he did it out of fear his wife would come after him.
Scott Phillip White had long denied murdering Scott Johnson who was found at the bottom of cliffs at Manly in 1988, only to say "guilty, I am guilty" during a pre-trial hearing in January.
He later told his confused lawyers, he "didn't (do it) but it's the only way, she's going to come after me".
White also said he was stressed and it was "too much", having seen the victim's brother and police in court, according to legal notes read in court on Tuesday.
"They are bad reasons, they're really bad reasons for pleading guilty and any lawyer acting responsibly would try to do as these lawyers have (and try to reverse the plea)," barrister Tim Game SC told the NSW Court of Criminal Appeal said.
"He had no advice at the point at which he pleaded guilty."
Mr Game, who began representing White recently, said it was in the interests of justice for the court to allow the cognitively impaired man to withdraw his plea and allow the matter to go to trial.
He rejected the Crown's assertion White made a plea of convenience, saying no lawyer would ever "plead someone up to murder" without knowing the facts.
While accused people trying to rescind a guilty plea may commonly give evidence, White's silence was of little significance given his lawyers' notes of his denials "immediately before and after" the plea, Mr Game said.
"I'd regard this situation as uniquely unusual - I've never seen anything like it," the barrister said.
The judge who heard the plea in January refused to allow White to reverse it and later sentenced the 52-year-old to at least eight years and three months in jail.
While a coroner in 2017 found Dr Johnson was violently attacked by someone who perceived him to be gay, Justice Helen Wilson found there was not enough evidence to show the murder was a gay hate crime.
Rather, she found White had reckless indifference to human life when he threw a punch at Dr Johnson near the unguarded edge of a high cliff and then fled without notifying police that Dr Johnson disappeared over the edge.
Mr Game said at the time of White's plea, that alleged liability wasn't contained in any document before the court and there was a "massive dispute" over the Crown's allegations.
NSW Director of Public Prosecutions Sally Dowling SC, representing the Crown, said the entire brief of evidence had been served on White's lawyers.
"There is no suggestion (White) was not very ably legally represented at every stage of this legal proceeding," she said.
Dr Johnson worked for NASA's Jet Propulsion Laboratory mapping the surface of Venus before moving to Australia in May 1986. He was working at the Australian National University at the time of his death.
His death was initially ruled a suicide, only for the case to be reopened in 2012 after pressure from his family.
Dr Johnson's brother, Steve, flew to Australia to attend Tuesday's hearing in Sydney, while several members of the Johnson family also viewed it online.
The hearing continues.
