The man accused of murdering Huddersfield backpacker Peter Falconio has launched a new appeal.

Lawyers in Australia have confirmed that Bradley John Murdoch, the man convicted of one of the most bizarre murders in history, has officially lodged an appeal.

Murdoch is serving life in jail for the murder of the Hepworth man, even though his body has never been found.

Mr Falconio vanished when he and his girlfriend, Joanne Lees, formerly of Almondbury, were ambushed during a trek through the Outback.

The Northern Territory Criminal Court of Appeal has confirmed that it received the application for leave to appeal from Murdoch’s lawyer.

And they are claiming improper behaviour by the prosecution.

Murdoch, 55, was convicted and sentenced to life in prison in 2005 for Mr Falconio’s murder.

He was also found guilty of the assault and deprivation of liberty of Mr Falconio’s girlfriend, Miss Lees.

The body of Mr Falconio has never been found despite a massive search by the Australian authorities.

On Tuesday Murdoch filed an application for leave to appeal in the Criminal Court of Appeal Northern Territory.

“This is an allegation that the crown prosecutor at the original trial, Rex Wild QC, improperly groomed the star crown witness Joanne Lees in how to give her evidence,” Murdoch’s barrister Peter Faris QC said in a statement.

“This allegation brings into question the entirety of Lees’ evidence.”

Murdoch has been serving his sentence, with a minimum non-parole period of 28 years, at the Alice Springs Correctional Centre.

Mr Falconio is believed to have been killed near Barrow Creek in July 2001, when he was 28.

He had been travelling with Ms Lees in a Kombi van on the Stuart Highway near Alice Springs, about 1,600 kilometres south of Darwin.

The 2005 trial of Murdoch was told that he had stopped the van at night and killed Mr Falconio, later disposing of his body.

Ms Lees escaped by eluding him in scrubland and later running on to the Stuart Highway where she was seen and rescued by a truck driver.

Murdoch has always maintained that he is innocent of the crimes.

His conviction was largely based on DNA evidence and the testimony of Ms Lees.

The family of Mr Falconio – who were in Australia for the duration of the trial – had pleaded with Murdoch to tell them what he had done with the body.

Miss Lees returned to Huddersfield and took up studies at university in Sheffield.

She also brought out a book about the case.

No date has been set for an appeal hearing.

A previous application by Murdoch for leave to appeal was dismissed by the Northern Territory Criminal Court of Appeal in 2007.