The Hutton Inquiry was prompted by the death of Dr David Kelly after he was named as the possible source of a BBC story on the government's Iraq dossier.

Lord Hutton called the death of Dr Kelly - a devoted husband and father and a public servant who had served the UK with "great distinction" - was a "great tragedy".

Lord Hutton said it was not possible to reach a conclusion about what Dr Kelly said to Mr Gilligan at their crucial meeting, and that it may be the scientist said more than he had intended to say and did not realise the gravity of the situation.

But, he said he believed the scientist did not tell Mr Gilligan the government probably knew or suspected the 45 minute claim was wrong when it drew up the dossier.

Lord Hutton said he agreed with suicide expert Professor Keith Hawton's opinion about the factors that led Dr Kelly to taking his own life, including a severe loss of self esteem and a feeling that people had lost trust in him.

Lord Hutton dismissed as "unfounded" claims reported by BBC journalist Andrew Gilligan on Radio 4's Today programme on 29 May 2003, which began the chain of events that would lead to the Kelly inquiry.

He criticised the defence correspondent's allegation in his first report that the government probably knew the claim that Iraq could launch weapons of mass destruction in 45 minutes was wrong.

This was a grave allegation which challenged the integrity of the government, he said.

Mr Gilligan resigned from the BBC in January 2004, in the wake of the criticism directed at him in the Hutton report.

The journalist said his departure was at his own initiative, but described the BBC collectively as the victim of a "grave injustice".

When Tony Blair's communications chief Alastair Campbell appeared before the Hutton inquiry he denied that the government attempted to "sex up" the Iraq dossier, against the wishes of the intelligence community.

In his judgement, Lord Hutton said he believed Mr Campbell was clear that nothing should be inserted into the dossier that went against the wishes of the Joint Intelligence Committee.

Mr Campbell resigned from his post as Tony Blair's director of communications part-way through Lord Hutton's investigation, but he said his departure was nothing to do with the inquiry, and was an attempt "to get a life back for me and my family".

Lord Hutton was appointed by the prime minister to head the inquiry which opened on 1 August 2003.

The peer, who retired as a Law Lord in January 2004, spent 10 years as Lord Chief Justice for Northern Ireland and had a legal career stretching back to the 1950s.

After interviewing over 70 witnesses during 22 days of hearings he delivered his 328 page report into the circumstances surrounding the death of the government weapons adviser Dr David Kelly.

In his main finding he said that the allegations made against the government by BBC reporter Andrew Gilligan that the 45 minute claim was known to be wrong and that the dossier was changed against the wishes of the intelligence community were both "unfounded".

Lord Hutton also said he was satisfied that Dr David Kelly had taken his own life.

The director general announced his resignation the day after Lord Hutton delivered his report.

He was the second senior member of the BBC to resign, standing down after Gavyn Davies quit as chairman of the BBC's board of governors.

Mr Dyke said that he hoped his resignation would draw a line under the affair.

In his report Lord Hutton found that the BBC's editorial system was defective, and he criticised BBC managers for not checking the detail of Andrew Gilligan's report on the government's dossier on Iraq.

Mr Dyke headed the BBC for four years after a long career in television.

Gavyn Davies announced his resignation after the Lord Hutton's report was published in January 2004.

Lord Hutton criticised the BBC governors and said they were wrong to rely on the BBC management's assurances over the reliability of Andrew Gilligan's report.

They should have taken a more hands-on role in investigating whether Mr Gilligan's claims were well founded, he said.