Dr David Kelly, 59, was the suspected mole behind a BBC report that Downing Street communications director Alastair Campbell "sexed up" a dossier setting out the case for war.

A senior officer said a knife and a packet of painkillers had been found close to where his body was discovered in woodland near his home in Oxfordshire on Friday.

Dr Kelly's family said he was a "loving, private and dignified" man, adding that recent events had made his life "intolerable".

The government will now hold an independent judicial inquiry into the circumstances surrounding his death.

The prime minister has faced tough questions over the government's handling of the affair.

He was asked if he had Dr Kelly's death on his conscience during a press conference in Hakone, Japan - the first leg of his Far East tour.

But Blair would only express his "deep sorrow" for Dr Kelly and his family and said: "I don't think it is right for anyone, ourselves or anybody else, to make a judgement until we have the facts."

He called for "respect and restraint" until the full circumstances were known.

Blair also refused to be drawn when asked if defence secretary Geoff Hoon or Campbell should resign over the affair.

Another reporter shouted: "Have you got blood on your hands Mr Prime Minister? Are you going to resign over this?"

The prime minister looked under "enormous emotional strain".

In a statement Hoon said the death of Dr David Kelly was "shocking and tragic".

"Our thoughts and sympathies are with his family," he said.

"It is only right that we do our utmost to establish the full circumstances surrounding this tragedy.

"Accordingly, the government has invited the Right Honourable The Lord Hutton urgently to conduct an investigation into the circumstances surrounding the death of Dr Kelly.

"The government will provide Lord Hutton with the fullest co-operation and expects all other authorities and parties to do the same."

Speaking to the BBC, Hoon said he took the welfare of all his staff seriously but did not accept that he had put pressure on Dr Kelly directly.

Confirming Dr Kelly's death, acting superintendent David Purnell said: "A post-mortem has revealed that the cause of death was haemorrhaging from a wound to his left wrist.

"The injury is consistent with having been caused by a bladed object.

"We have recovered a knife and an open packet of Co-Proxymol tablets at the scene."

He said police inquiries were continuing but there was no indication at this stage of any other party being involved.

The judicial inquiry is expected to take a matter of weeks not months.

Dr Kelly disappeared two days after being grilled by the Commons foreign affairs select committee as part of its inquiry into the use of intelligence in the run-up to the war in Iraq.

The former Labour minister Glenda Jackson said blame lay with Downing Street, who used a battle with the BBC to divert attention from the failure to find weapons of mass destruction in Iraq.

She said Tony Blair's credibility had been "holed below the waterline" and it was time for him to resign.

A BBC spokesman said: "We are shocked and saddened to hear what has happened and we extend our deepest sympathies to Dr Kelly's family and friends."

Dr Kelly leaves a wife, Janice, and three daughters Sian, 32, and 30-year-old twins Rachel and Ellen.