By Danny Shaw BBC Home Affairs Correspondent

Convicted killer Michael Shirley is waiting for an appeal court ruling which could clear him of the murder and rape of a 24-year-old woman more than 16 years ago.

Just after midnight on 9 December 1986, a 24-year-old barmaid, Linda Cook, was walking home from a friend's house on the Buckland Estate in Portsmouth. It was only a mile or so - but she never made it.

Michael Shirley has always protested his innocence

Linda's half-naked body was found on waste-ground near a school playground. She had been brutally raped and strangled. The attacker had stamped on her body - breaking her jaw and spine and crushing her larynx.

Linda's death came during a spate of unsolved sex attacks in the area. Hampshire police were under intense pressure to find the killer, who was dubbed the Beast of Buckland.

And the police appeared to have a valuable clue. The killer, in carrying out the frenzied attack, had left a distinctive shoeprint on Linda's stomach. The logo was clearly visible: "Flash".

If police could trace the shoes that had left the mark, they would get the killer.

Shore leave

The hunt for the shoes led the case to be called the Cinderella Murder. And it was the shoe evidence that appeared to link the killing so clearly to Michael Shirley.

In December 1986, Shirley, an 18-year-old Royal Navy sailor from Leamington Spa in Warwickshire, was on shore leave. His ship, the Apollo, had docked in Portsmouth, and on the night of Linda Cook's murder he had taken a taxi to the Buckland Estate, close to the murder scene, to drop off a young woman he had met at a nightclub.

When police arrested Shirley he had cuts and scratches on his body and bloodstains on his trousers. Detectives suspected that both came about during the attack.

Most significantly, he owned a pair of Flash shoes: the make was the same as those which had left the footprint; the size was similar too.

Rooftop protest

In January 1988, Shirley was charged with the rape and murder of Linda Cook; a year later, at Winchester Crown Court, he was convicted by an 11 to one majority.

But Shirley has always maintained his innocence. After he was refused leave to appeal in May 1989, he began a campaign to secure his release. It involved a hunger-strike, that almost cost him his life, and a prison rooftop protest, though his denials of guilt have arguably cost him the opportunity of getting parole.

Doubts about the safety of the conviction began to spread when, in 1992, his case was one of 110 named as possible miscarriages of justice in a dossier given to the Home Office.

Eventually, the Criminal Cases Review Commission examined the case - and decided that it should be reviewed by the Court of Appeal.

According to Michael Shirley's lawyers, the CCRC discovered that the blood found on his clothes was his own, and not Linda Cook's. It emerged that the scratches on his body might have been there for some time before the murder.

Semen sample

A taxi-cab's log-book, which lawyers say was not disclosed to the defence at the trial, suggested that Shirley was not on the estate at the time of the murder.

And the CCRC said DNA tests showed that a sample of semen recovered from Linda's body came from someone else - could they have been the killer and not Shirley?

Of course the Flash shoes still provide compelling evidence. But many thousands of pairs had been sold in the year that Linda Cook was murdered, and it appears that, despite exhaustive tests, the prosecution has found none of Linda Cook's DNA on the pair owned by Michael Shirley.

However, the Crown are contesting the appeal: many potential miscarriages of justice, which appear to have strong grounds, can fail under the forensic glare of experienced judges.

Michael Shirley - who has spent over 16 years in prison for a crime he maintains he did not commit - will be as aware of that as anyone as he listens to proceedings from the dock at the Court of Appeal.