A group of medical experts has demanded a full inquest into the death of government weapons inspector Dr David Kelly saying it unlikely he could have bled to death in the way the authorities claim.
They described the official cause of death, haemorrhage, as "extremely unlikely" in the light of evidence since made public.
The call came in a letter to a newspaper signed by eight senior figures, including a former coroner, Michael Powers, a former deputy coroner, Margaret Bloom, and Julian Bion, a professor of intensive care medicine.
Coalition ministers are exploring how best to allay concern over shortcomings in the official version of Dr Kelly's death.
The scientist was found dead in woods near his Oxfordshire home in 2003 after he was exposed as the source for a BBC story disclosing anger within the intelligence service over use of Iraq arms data.
The then Lord Chancellor, Lord Falconer, suspended an inquest before an inquiry by Lord Hutton began, and it was never resumed.
Lord Hutton concluded "the principal cause of death was bleeding from incised wounds to his left wrist which Dr Kelly had inflicted on himself with the knife found beside his body".
But the letter's signatories insist that the conclusion is unsafe. They argue that a severed ulnar artery, the wound found to Dr Kelly's wrist, was unlikely to be life-threatening unless an individual had a blood clotting deficiency.
"Insufficient blood would have been lost to threaten life," they write. "Absent a quantitative assessment of the blood lost and of the blood remaining in the great vessels, the conclusion that death occurred as a consequence of haemorrhage is unsafe."