Briefing: Will the man jailed for Jill Dando's murder be freed?

Appeal verdict imminent on conviction that rested on a single speck of firearms residue

Who is Barry Bulsara?

His real name is Barry George: an eccentric, isolated man who adopted the name Bulsara to copy the birth name of Queen's lead singer, Freddie Mercury. This week, George should find out whether he has won an appeal against the life sentence he was given six years ago for shooting Jill Dando. The presenter of the BBC's Crimewatch was murdered on the doorstep of her home in Fulham, south-west London, in 1999.

The jury returned a 10-to-one majority guilty verdict after eight weeks of legal argument and five days of deliberation. The murder sparked a massive police manhunt and George, who lived half a mile from Ms Dando, came to light through routine police inquiries. He maintained his innocence throughout the trial.

So, was there strong evidence to convict him?

At the time of the original trial, it seemed so.

Robin Keeley, a forensic expert who worked for the Forensic Science Service, presented evidence to the jury. Mr Keeley told them that he had found a microscopic particle of firearms residue on the inside of a coat belonging to Mr George, which was seized during a police search of his home in April 2000, one year after Ms Dando's murder.

Mr Keeley told the jury the particle was "similar" to and "consistent" with other particles found on Ms Dando's hair and coat. The prosecution told the jury the evidence was "compelling" and linked Mr George to the crime.

What has changed, then?

The Criminal Cases Review Commission (CCRC) has referred his conviction back to the Court of Appeal after a five-year inquiry because it has uncovered new evidence that undermines the reliability of this crucial piece of forensic evidence. The commission has issued a statement saying that not only is the particle evidence unreliable, it may not even be as significant as was originally thought.

The CCRC interviewed Mr Keeley in November 2001 and he said he had a "vague unease" about the significance attached to the particle during the trial. Mr Keeley went so far as to tell the CCRC that: "The weight of evidence associated with the finding of a single particle was zero."

A BBC Panorama investigation took the unusual step of interviewing members of the original jury. One, the jury's foreman, told Panorama that had the particle not formed the crux of the case against Mr George, then the prosecution case would have failed and the jury would have returned a different verdict.

So shouldn't George have used this to lodge an appeal before now?

Well, he did appeal before, in 2002, but he was unsuccessful. What he didn't know then was that Mr Keeley had met the CCRC in 2001 and expressed his concern that the court had not been left with the right impression after the original trial. Neither this, nor the disquiet of other forensic experts, was passed on to Mr George's legal team for his appeal.

So what does the CCRC say now about Mr Keeley's evidence?

The CCRC has concluded that the particle evidence should not have been admitted during the case because Mr Keeley did not make it clear to the jury that it was inconclusive.

So, is he guilty or what?

That is for the Court of Appeal to decide. Mr George certainly has a wide base of supporters who say he has committed no crime. But others, such as Ms Dando's former co-presenter Nick Ross, say he is guilty and that the particle is not even central to the case. He argued yesterday in a newspaper article that George was placed at the scene of the crime, or nearby, by two witnesses shortly before and after the murder took place and that he later went back to persuade these people that he had been there at different times and wearing different clothes.

Mr Ross said a series of circumstantial pieces of evidence against George, such as him reputedly taking pictures of TV presenters on his television, an obsession with guns and a history of violence against women and stalking them, points to his guilt.

What can the Court of Appeal do about all this?

It could quash the guilty verdict and order Barry George's immediate release. The Court of Appeal could also order a retrial or it could say that, even without the forensic evidence, the jury reached the right verdict in the first place. While this seems unlikely, if it happens, George will continue to serve his life sentence.