Serial killer Robert Black's criminal past was wrongly revealed to a jury who found him guilty of kidnapping and murdering a schoolgirl, appeal judges have heard.
Judges were also told that the 65-year-old Scot's trial of killing Jennifer Cardy in Northern Ireland should have been halted due to a lack of identification evidence against him.
Black is attempting to overturn his conviction for murdering the nine-year-old. She was abducted as she cycled to a friend's house in Ballinderry, Co Antrim, in August 1981.
Her body, suspected of being sexually abused, was discovered nearly a week later at a dam near Hillsborough, Co Antrim.
Black, a former delivery driver from Grangemouth, near Falkirk, was given his 12th life sentence in 2011 for the murder and will be 89 before he can apply for parole.
In 1994, he was found guilty of three unsolved murders from the 1980s as well as a failed abduction bid from Nottingham in 1988. He kidnapped and murdered Susan Maxwell, 11, from the Scottish Borders, Caroline Hogg, five, from Edinburgh and Sarah Harper, ten, from Morley near Leeds.
But opening his case at the Northern Ireland Court of Appeal in Belfast, defence counsel David Spens QC said: "The trial judge erred in admitting evidence of the defendant's bad character. He detailed the discovery of child porn and objects used for self-abuse in the appellant's home.” Black's sex fantasies about abducting young girls, recorded in 2005 during his interviews with detectives investigating Jennifer's case, were also played at trial.
Mr Spens added: "The Crown suggested that those fantasies where in fact a reflection of what he had done to Jennifer Cardy. The defence point was that they were nothing more than a fantasy."
Mr Spens further contended that the trial judge should have stopped the case at the end of the prosecution case on the basis that available identification evidence was insufficient to prove Black carried out the murder.
He told Lord Chief Justice Sir Declan Morgan, Lord Justice Higgins and Lord Justice Girvan: "All the court would have had would have been evidence of opportunity and evidence of propensity. Nothing more." The appeal continues.