The Government has rejected calls for a new inquiry into the death of weapons expert Dr David Kelly following claims in a book by Lewes MP Norman Baker that he may have been murdered.

Lord Hutton's report into the death of the scientist concluded that Dr Kelly had committed suicide, but Mr Baker, in a book published late last year, said Dr Kelly was probably the victim of a group of Iraqi exiles.

Dr Kelly's comments to the journalist Andrew Gilligan about weapons in Iraq sparked a long-running row between Downing Street and the BBC which was still continuing when Dr Kelly was found dead in woods near his Oxfordshire home in July 2003.

Labour peer Lord Berkeley said at Lords question time: "The new book by Norman Baker concludes that the suicide of Dr Kelly would be extremely unlikely and certainly not proven beyond reasonable doubt.

"The Hutton inquiry was not a statutory one and no evidence was taken under oath, so isn't it now necessary for the Government to set up a proper statutory inquiry to investigate fully the circumstances of this senior Government employee."

Lord Hutton concluded that Dr Kelly died by cutting his left wrist and taking co-proxamol painkilling tablets.

Justice Minister Lord Hunt this week described Mr Baker's book as "a good Christmas read".

But he told peers: "There was a thorough inquiry by Lord Hutton which reached the conclusion that Dr Kelly committed suicide.

"Lord Hutton was satisfied no other person was involved in the death of Dr Kelly because a very lengthy examination, of the area where his body was found, by police officers and by forensic biologists found no traces whatever of a struggle or involvement by a third party.

"And the wounds to Dr Kelly came from a knife from his study in his home and it was highly unlikely that a third party could have forced Dr Kelly to swallow a large number of co-proxamol tablets."

Mr Baker repeated calls for new inquiries into the Iraq war and Dr Kelly's death.

He said: "I am very pleased that Lord Berkeley took the decision to raise this matter in the House of Lords and to call for a new inquiry into the death of Dr Kelly.

"The Hutton Inquiry was far from thorough, as the minister claimed, but was an incomplete, flawed inquiry which left many very important questions unanswered.

"What I would like to see now is both a proper inquiry into the whole fiasco of the Iraq war, and a re-opening of the inquest into the death of the country's most eminent weapons inspector."