Barry George, the man convicted of shooting the television presenter Jill Dando in the head at close range eight years ago will begin his latest attempt to overturn his conviction today.

He was granted a new appeal after a five-year review by the Criminal Cases Review Commission raised concerns about forensic science evidence.

The case hinged on a speck of gunshot residue found in George’s jacket pocket that prosecutors said was consistent with residue found on Dando’s hair and clothing.

During a three-day hearing at the Court of Appeal it is believed that lawyers for George will claim that the particle could have been transferred through the air.

The commission granted George his appeal in June after “a thorough and intensive review”. In a statement it said: “The referral is based on new evidence which calls into question the firearms discharge evidence at trial and the significance attached to that evidence. To refer a conviction to the Court of Appeal, the commission must decide there is a ‘real possibility’ that the conviction, if referred, will be quashed.

“This test is set out in the Criminal Appeal Act. The commission has in this case concluded that the new evidence regarding the firearms’ discharge does raise such a real possibility.”

A recent investigation by Panorama on BBC One spoke to a member of the original jury who said that if the particle had not formed a crucial part of the case against George the prosecution would have failed.

The programme also claimed that a witness saw armed police enter George’s flat and retrieve the jacket where the particle was found a year after the murder. This has been denied by police.

Detectives say that if George, 47, is cleared on appeal it is unlikely that the investigation would be reopened.

Supporters of George, encouraged by two new documentaries casting serious doubt on his conviction, say that they are confident that a retrial, at least, will be granted. A previous appeal by George was turned down in 2002.

Jeremy Moore, George’s solicitor, has said that three forensic science experts would be called to challenge the firearms evidence produced in the original trial in 2001. The Crown Prosecution Service will argue that there were other, sufficient strands to its case to convict George. Police believe that identification evidence was crucial.

Dando, the co-presenter of Crimewatch on BBC One, was murdered on the doorstep of her home in Fulham, southwest London, in 1999. George, who lived half a mile from her, was arrested a year after her murder when he came up in routine police inquiries.

Nick Ross, the close friend and former colleague of Dando on Crimewatch, has written to the Appeal Court judges urging them not to be swayed by recent conspiracy theories.

Robert Charig, a friend of George, said: “Barry is optimistic, given the changes in evidence rules. He is very keen to get the appeal started. He has been wrongfully incarcerated for six years, which is a long time.”

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