There were fresh calls today for a formal inquest to be held into the death of Government scientist David Kelly.
A group of campaigning doctors have produced a report arguing that the Hutton Inquiry's finding of suicide was flawed and have handed it to lawyers preparing a legal challenge.
Dr Kelly's body was found six years ago on Friday in woods near his Oxfordshire home after he was exposed as the source of a BBC report on the grounds for going to war in Iraq.
Instead of a coroner's inquest, Lord Hutton was asked by then Prime Minister Tony Blair to conduct an investigation.
His inquiry concluded the 59-year-old died from blood loss as a result of cutting his wrist with a blunt gardening knife.
According to the team of 13 specialist medics, however, a cut to the ulnar artery was "highly unlikely" to have caused enough bleeding to kill Dr Kelly.
Autopsy reports should be provided to enable their questions to be answered, the doctors added.
One of the authors, retired consultant in orthopaedic and trauma surgery David Halpin, said previous examinations into Dr Kelly's death were "flawed".
Lord Hutton was charged with inquiring into the circumstances surrounding the death and not the cause itself and his inquiry did not have the same legal standards as a coroner's inquest, he said.
"Due process has been subverted," he said. "The group that I am part of is not prepared to let that go. There is evidence of a cover-up." Mr Halpin, 69, who lives in Devon, described Dr Kelly as a "skilled" and "courageous" man who deserved a "proper inquest".
He said: "He was a very prominent germ and chemical warfare expert. That is relevant because of his knowledge of the biology of death. He had spent 10 years at Porton Down (a Government laboratory) and he knew everything about killing things.
"So to take what was said to be a blunt knife and what was alleged to be his wife's co-proxamol tablets to try to kill himself is extraordinary. I think it's highly likely he was assassinated."
The doctors' report setting out their rejection of the theory Dr Kelly died of a haemorrhage will also be sent to Sir John Chilcot's forthcoming inquiry into the Iraq War.
Liberal Democrat MP Norman Baker, who published a book about Dr Kelly's death two years ago, backed the doctors' campaign.
He said: "There are three aspects of 2003 which need to be put to bed.
"There needs to be a proper inquiry into the Iraq War, there needs to be a proper inquest into Dr Kelly's death and there needs to be some recognition of his outstanding work.
"All we are asking for is proper legal process - we have not had it yet."
The calls come ahead of the screening in London of a documentary featuring Dr Kelly's work.
Investigative journalist Bob Coen's film Anthrax War will be shown at the Frontline Club on Friday - the anniversary of Dr Kelly's death.