The murder of the six-year-old boy, who was strangled to death in woods near Peterborough, was among the most high-profile cold cases in Britain until DNA was identified on the victim's clothes following a re-examination of the evidence two decades later.

James Watson, who was 13 at the time of the killing, denied murder but was found guilty by a jury and sentenced to life with a minimum term of 15 years at the Old Bailey in June last year.

The 42-year-old appeared at the Court of Appeal in London on Tuesday via video link from Wakefield prison to challenge his conviction.

Jennifer Dempster KC, acting for Watson, told the court there had been a "total disregard" towards preserving exhibits in the case.

She said: "The reality, we submit, was that this was a wholesale loss and destruction of evidence, so much so that a fair trial of this applicant is no longer possible.

"It closed down completely any opportunity for the defence to explore the potential of other suspects."

The barrister described how the wheelie bin where Rikki's clothes were found was "last seen" in an underground car park before it went missing, stopping it being searched it for DNA or fingerprints.

Ms Dempster added: "It is the developments in DNA technology that have taken place that enabled the Crown to bring this applicant to trial, but it is those very same advances in technology that the applicant has been completely deprived of."

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However, John Price KC, for the Crown, told the court that there was no evidence Watson's case had been affected.

He said: "The applicant failed to demonstrate that there was any prejudice caused to him by the loss of the material that has been identified.

"If there was... we do not accept that it was not capable of being ameliorated in the usual way."

Mr Price added: "The loss of a speculative position is not prejudice."

At the end of the hearing, Lord Justice Holroyde, sitting with Mr Justice Morris and Judge Angela Morris, said they would give their decision in writing at a later date.

"We will do it as soon as we can," the judge said.