A man jailed after unexpectedly pleading guilty to the murder of American mathematician Scott Johnson has had his conviction quashed.
Scott Philip White was handed a 12-year jail sentence in May, more than three decades after Mr Johnson's body was found at the base of cliffs at North Head, near Manly, in 1988.
White surprised his lawyers by pleading guilty during a pre-trial hearing in January, but now maintains his innocence.
Today, the NSW Court of Criminal Appeal quashed White's conviction and sentence.
This will likely result in White facing a NSW Supreme Court trial for the murder of Mr Johnson.
Mr Johnson's death — one of Sydney's longest running mysteries — had been the subject of three coronial inquests and a $2 million reward for information that lead to a conviction.
Supporters and relatives of Mr Johnson had long argued his death was a gay hate crime.
Outside court friend Peter Rolfe said he was disappointed by the latest court decision.
"This matter has been going on for so long," he said.
"And it just goes on and on and on."
Prior to White's arrest, one inquest found Mr Johnson took his own life, another returned an open finding while the third ruled his death was the result of a gay hate crime.
Chief Justice Andrew Bell, and Justices Richard Button, and Natalie Adams today also set aside the previous judge's dismissal of White's application to withdraw the plea of guilty.
White's lawyers had argued the Supreme Court judge erroneously denied his application to withdraw the plea, and had applied the wrong legal test.
They also said it came at a time when the Crown case had not been particularised and highlighted his consistent prior denials of the offence.
Justice Helen Wilson sentenced White in May, but also said there was not enough evidence to deem the murder a gay hate crime "beyond reasonable doubt".
Johnson's brother, Steve, travelled to Sydney from the United States to attend the two-day appeal hearing.
He said he accepted the possibility that he might have to sit through a trial.
Detective Chief Inspector Peter Yeomans said Steve Johnson was "very very disappointed to say the least," while Mr Rolfe confirmed he was determined to be here for any future court appearances.
"I was hoping Steve wouldn't have to go through that but it appears he has to," Mr Rolfe said.
The case will return to court for mention on December 1.
