A MURDERER who beheaded his teenage victim has lost an appeal against his conviction.

Stewart Michael Diamond, 30, had been out of prison for just three months in 1997, when he brutally strangled Christopher Hartley in a bedsit and hacked him to pieces in the bathroom.

The 17-year-old's remains were found in a bin and a sports bag at the back of a hotel. His head has never been found.

Christopher grew up in Burnley attending Myrtle Bank and Harger Clough Primary Schools. He was also a pupil at Tullyalan Special School in Darwen. His murder took place in Blackpool where his brother and sister lived.

Diamond was convicted of murder in January 1999 at Preston Crown Court and sentenced to life behind bars.

In the Appeal Court, his legal team argued his conviction was "unsafe", because he was not fit to give proper instructions to lawyers at his trial and had been suffering from an 'abnormality of the mind', which impaired his responsibility for the killing.

Diamond was described as an 'extremely dangerous' paranoid schizophrenic.

Lord Justice Thomas, sitting with Mr Justice Irwin and Mr Justice Coulson in London, dismissed the appeal.

Lord Thomas said: "We do not accept any of the accounts given by Diamond; in the light of the history we have set out, and of the differences in his account of the killing and the objective evidence, we could not do so.

"It is, in our view, very significant that he only finally admitted he was the killer in 2006, when all other avenues of appeal were at an end and his only hope was to advance the defence of diminished responsibility."

The justices said Diamond suffered with mental disorders since he was a child.

His first criminal offence was at the age of 14, when he robbed a post office at knifepoint. He then went on to commit a host of other offences, including attacking his stepmother and stabbing a resident at a hostel.

The judge said that, during one period of detention, he confessed to a doctor that he 'fantasised about killing someone and cutting them up'.

In December 1996, he was detained for 18 months in a young offender's institution for stabbing a youth in the head, and it was just under three months after his release that he killed Mr Hartley.

Diamond's lawyers asked the Appeal Court to overturn his murder conviction and substitute a verdict of manslaughter.