Ex-Conservative leader Michael Howard has urged a full inquest into the death of government scientist Dr David Kelly.
He told the Mail on Sunday "serious questions" had been raised by experts who said the official cause of death was "extremely unlikely".
Dr Kelly died in 2003 after he was exposed as the source of a BBC story on the grounds for going to war in Iraq.
An inquiry found the 59-year-old had died from blood loss after slashing his wrist with a blunt gardening knife.
Michael Howard, who is now a Tory peer, led his party at the time the scientist's body was found in woods near his Oxfordshire home.
He told the newspaper: "In view of the growing number of relevant questions that have arisen and cast doubt on the conclusions reached by Lord Hutton, I believe it would now be appropriate for a full inquest to be held.
"Recent evidence by the first police officer on the scene, together with new statements by doctors, raise serious questions which should be considered.
"This has been on my mind for quite a while and recent events have crystallised my view."
Last week, a group of prominent experts cast doubt on the official cause of death.
They wrote a letter to The Times arguing 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.
The letter's signatories included a former coroner, Michael Powers, a former deputy coroner, Margaret Bloom, and Julian Bion, a professor of intensive care medicine.
When former prime minister Tony Blair appointed Lord Hutton to head the public inquiry into the scientists's death, the then lord chancellor, Lord Falconer, unusually ruled it should also act as an inquest.