"Hopeless and incompetent" detective work has thrown a huge question mark over the case against Sarah Payne's alleged killer, a court heard.

Roy Whiting's barrister, Sally O'Neill, made the accusation in the final minutes of her defence closing speech at Lewes Crown Court yesterday.

She urged the jury to "totally disregard" a key piece of evidence which allegedly provides billion-to-one proof it was Whiting, 42, who snatched the schoolgirl from a country lane, killed her and buried her.

The court has been told a single strand of Sarah's hair was found on a sweatshirt recovered from the builder's van when he was arrested at his bedsit in St Augustine Road, Littlehampton, 24 hours after Sarah vanished.

Later in the trial, it emerged the sweatshirt had been among a bundle of 55 exhibits sent up to forensic labs in London in the same van. Among them were two hairbrushes taken from the Payne family home by PC Eric Prior, stray hairs from which were found stuck to the outside of eight other exhibit envelopes.

Miss O'Neill said: "You may find this evidence rather shocking. It's not just that the hopeless and incompetent Mr Prior and the equally incompetent detective sergeant have managed to achieve this degree of contamination of an important exhibit in an important case, it's that nobody seems that bothered about it.

"This is not a fly-by-night bit of defence. This isn't something we have magicked out of nothing to muddy the waters as far as the prosecution's 'compelling' case is concerned.

"It's a serious and very troubling point."

Miss O'Neill said Ray Chapman, who oversaw all of the forensic investigations, had been flippant and dismissive about the finding.

It is the defence case one of these stray hairs somehow managed to find its way from the outside of an envelope on to Whiting's sweatshirt as it was examined in the lab.

Miss O'Neill reminded the jury the hair was not spotted by scenes of crime officer Anna Maxwell when she photographed the garment two days after it was seized. Miss O'Neill concluded: "It's quite possible the hair got on to this sweatshirt as a result of completely shoddy collection of exhibits."

Earlier, the court listened as Miss O'Neill tried to unpick the strands of evidence which the prosecution says can be built up into a picture painting Whiting's guilt in "compelling clarity".

Miss O'Neill said the only evidence remaining were the 22 links between Whiting and Sarah revealed by fibres found on the girl's shoe and in clumps of hair taken from her graveside.

She turned to the jury and said: "What else in reality do you have? We submit that the complete absence of any scientific evidence, body fluids, fingerprints, anything in the back of the van, is crucial.

"With this sort of extensive fingertip search they would have found something. They kept digging for 18 months and all they came up with at the end of that intensive investigation was fibres."

Sarah, eight, vanished from a country lane in Kingston Gorse while out playing with her brothers and sister on July 1 last year. Her body was found 16 days later. Whiting denies kidnap and murder.

The trial continues.

8 December 2001