A group of doctors campaigning for a full inquest for David Kelly have made a last-ditch plea to Prime Minister David Cameron to intervene on their behalf.

Attorney General Dominic Grieve is considering a dossier of evidence provided by the doctors in September, and is expected to announce soon whether he will ask the High Court to order an inquest.

In an open letter to Mr Cameron, the doctors warned they will seek judicial review if Mr Grieve decides no inquest is needed.

The Hutton Inquiry into Dr Kelly's 2003 death found the Government weapons inspector committed suicide. Then Justice Secretary Lord Falconer ruled Lord Hutton's inquiry could take the place of an inquest in the coroner's court.

But the doctors, led by Stephen Frost, say Hutton failed to examine a number of questions over the circumstances surrounding the discovery of Kelly's body in woodland near his Oxfordshire home, soon after he was named as the source of BBC reports questioning the accuracy of a Government dossier arguing the case for war in Iraq.

In the letter, the doctors denounced the Hutton report as a "whitewash" which "failed adequately to address the cause of death itself and the manner of death".

Urging Mr Cameron to "endorse" their call for an inquest, they pointed out Lord Hutton spent only half a day of his 24-day inquiry considering the cause of Kelly's death. And they argued: "No coroner in the land would have reached a suicide verdict on the evidence which Lord Hutton heard.

"The coroner is required to hear evidence which constitutes proof beyond reasonable doubt that the deceased killed himself and that he intended to kill himself, before he may return a verdict of suicide. Lord Hutton did not hear evidence which came near to satisfying that test."

The letter stated: "Lord Hutton's finding of suicide is clearly unsafe and may, especially given the extraordinary context of Dr Kelly's death, represent one of the gravest miscarriages of justice to occur in this country."

The doctors cautioned Mr Cameron: "If an inquest is denied, despite all the evidence carefully provided to the Attorney General, there is a real and grave risk that your Government will be seen as continuing, and being complicit in, an enormous conspiracy to pervert the course of justice."