The man jailed six years ago for the murder of Jill Dando was found guilty on the basis of “deeply flawed” evidence, the Appeal Court was told yesterday.

Barry George, 47, was described by his own lawyers as a fantasist and loner with learning difficulties, as he sat in the dock at the Royal Courts of Justice for the start of his second appeal.

He wore a dark blue suit over a bright blue open-necked shirt and spoke only once, to confirm his identity as Barry Michael George.

Alongside him and his three security guards was Dr Susan Young, a clinical psychologist, whose role was to help him to follow the progress of the case. She was also his companion throughout the original trial.

William Clegg, QC, told the court that George’s conviction was unsafe. “He is a man who has learning difficulties. His intellectual functioning is in the borderline range. He suffers from epilepsy and has severe cognitive impairment,” he said. “He had a tendency to fantasise and was on record as claiming to be related to Freddie Mercury and having served in the SAS.”

Mr Clegg said that the case against George, who lived near Miss Dando, had been “significantly weakened” by a new assessment of the value of a microscopic particle of gunshot residue found in George’s coat pocket.

Mr Clegg told the court that expert witnesses would say that the tiny fragment — 1/2,000th of an inch in size — had no probative value. The view of respected forensic scientists was that the firearms particle was just as likely to have been found on George’s coat whether or not he had fired the shot that killed Miss Dando.

If George’s appeal is successful it is likely to open the door to a retrial.

Miss Dando, 37, a newsreader and a presenter of the BBC programmes Crimewatch and Holiday, was killed outside her home in West London in April 1999. Her killer had pressed a gun against her forehead and fired once.

George gave a witness statement to police almost a year later. During a subsequent search of his flat officers seized the coat on which the gunshot particle was found. He was placed under covert surveillance until May 25, 2000, when he was arrested.

An Old Bailey jury convicted him of murder by a ten-to-one majority verdict in July 2001. A year later his first appeal against conviction was dismissed.

George’s second appeal follows a referral by the Criminal Cases Review Commission and is confined to the significance of the gunshot particle.

Mr Clegg said that particle was “an important part of the prosecution case” in the original trial and that without it the Crown case against George was much weaker. After the trial, there was concern within the Forensic Science Service (FSS) that the evidence about the gunshot particle may have been given “undue weight”.

Scientists at the FSS said that, at best, the presence of the particle should have been a “neutral” factor and should not have become a central plank of the prosecution case.

Two forensic scientists prepared a report for the Criminal Cases Review Commission that concluded: “It would be just as likely that a single particle of discharge residue would have been recovered from the pocket of Mr George’s coat whether or not he was the person who shot Ms Dando a year previously.”

Mr Clegg said that retesting of the scientific material had found a second tiny particle of firearms residue on tapings taken from the garment.

This, he said, added weight to the theory that the particles had attached themselves to the coat close to the time of George’s arrest.

Mr Clegg continued: “It is generally accepted that firearms discharge residue will not remain on a garment that is being worn for more than about ten hours at most. This was agreed evidence at trial.

“Commonsense demands that this particle can certainly be excluded as having attached itself to the coat, almost a year before, when Jill Dando was shot.”

Mr Clegg said that the Crown would have “considerable difficulty in establishing a prima facie case” without the firearms evidence.

He added: “It is to be remembered that this was a majority verdict after a very long retirement. Although there was clearly other important evidence in addition to the firearms residue, the effect of neutralising the firearms residue must render the conviction unsafe.”

Speaking outside court afterwards, George’s sister, Michelle Disken, said: “We’re very grateful to them that we can actually be back here today — and today we’re hoping that we’re going to get justice at last for Barry.”

The hearing continues.

Concerns have been raised about the broadcast of TV documentaries about the case in the fortnight before the appeal opened.

Lord Phillips of Worth Matravers, the Lord Chief Justice, said that neither he nor his fellow judges – Lord Justice Leveson and Mr Justice Simon – saw Panorama on BBC One or Dispatches on Channel 4. He said: “It may be appropriate afterwards to consider the propriety of these broadcasts.”

He added that the judges had received correspondence about the case that they had not read. “If anyone has anything they think should be brought to the attention of the court, it is to be done through the lawyers involved.”

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