Legality of warThe British Attorney General Lord Goldsmith advised Mr Tony Blair that war in Iraq would be legal under international law so long as the Prime Minister was satisfied that Saddam Hussein had failed to co-operate with United Nations weapons inspectors, according to the Butler report.
According to the Attorney General, the existing UN Security Council resolution 1441 - and the earlier resolutions 678 and 687, passed at the time of Iraq's invasion of Kuwait - already contained authorisation for military action in this case, without the need for a fresh resolution specifically triggering war.
Lord Butler's report did not pass judgment on Lord Goldsmith's interpretation of the law, beyond saying that intelligence information played only a limited role in shaping it.
But Lord Butler did raise concerns about the failure of Mr Blair and the intelligence agencies to reassess their view of Saddam's actions in the weeks before the outbreak of hostilities, in order to be certain that he was in fact defying inspectors and that the war was therefore legal.
Saddam's December 2002 dossier on his biological and chemical activities had been swiftly dismissed as flawed, and had not been re-evaluated in the light of the failure of UNMOVIC inspectors to find any evidence of WMD programmes, the report said.
"Despite its importance to the determination of whether Iraq was in further material breach of its obligations under Resolution 1441, the Joint Intelligence Committee made no further assessment of the Iraqi declaration beyond its initial assessment," said the report.
"We have also recorded our surprise that policy-makers and the intelligence community did not, as the generally negative results of UNMOVIC inspections became increasingly apparent, re-evaluate in early 2003 the quality of the intelligence."
Lord Goldsmith was initially called in by the government before the adoption of Resolution 1441 in November 2002.
He concluded then that there was "no justification for the use of force against Iraq on grounds of self-defence against an imminent threat", said the report.
His advice was sought once more following the unanimous agreement of the Security Council to 1441, which gave Iraq a "final opportunity" to comply with the disarmament requirements imposed at the end of the 1991 Gulf War and threatened "serious consequences" if it failed to do so.
There was disagreement within the Foreign Office over whether this wording authorised war in the event of Saddam failing to co-operate or whether a second resolution would be required stating that he had not complied and explicitly approving military action.
Foreign Secretary Mr Jack Straw told the Butler Inquiry he believed a second resolution was not necessary. His deputy legal adviser, Elizabeth Wilmshurst, resigned because she could not accept this argument.
Following discussions with Mr Blair, Mr Straw and officials, including the UK ambassador to the UN Sir Jeremy Greenstock, Lord Goldsmith concluded that 1441 did authorise military action if the Prime Minister was sure Saddam had failed to comply.
The advice required the Prime Minister "in the absence of a further UN Security Council resolution, to be satisfied that there were strong factual grounds for concluding that Iraq had failed to take the final opportunity to comply with its disarmament obligations under relevant resolutions of the Security Council, and that it was possible to demonstrate hard evidence of non-compliance and non co-operation."