LONDON (AFP/REUTERS) - Britain's Iraq War Inquiry report on Wednesday heavily criticised intelligence, military and political leadership under then prime minister Tony Blair in the run-up to the 2003 invasion and during the conflict.
Here are four key conclusions from the damning 2.6 million word report by retired civil servant John Chilcot:
'I WILL BE WITH YOU, WHATEVER'
"I will be with you, whatever," said Blair's note to then US president George W. Bush on July 28, 2002 - nearly a year before the March 2003 invasion.
"By early January (2003), Mr Blair had also concluded that 'the likelihood was war'. At the end of January, Mr Blair accepted the US timetable for military action by mid-March," the report said.
It concluded that Blair "set the UK on a path leading to diplomatic activity in the UN and the possibility of participation in military action in a way that would make it very difficult for the UK subsequently to withdraw its support for the US."
Blair "did not press President Bush for definite assurances about US plans, did not consider or seek advice about whether the absence of a satisfactory plan called for reassessment of the terms of the UK's engagement and did not make agreement on such a plan a condition of UK participation in military action".
"In the absence of a majority in support of military action, we consider that the UK was, in fact, undermining the Security Council's authority".
The report said that Britain chose to join the invasion of Iraq before peaceful options for disarmament had been exhausted:
"At the time of the parliamentary vote of 18 March, diplomatic options had not been exhausted. The point had not been reached where military action was the last resort."
"It is now clear that policy on Iraq was made on the basis of flawed intelligence and assessments. They were not challenged, and they should have been.
"Judgments about the severity of the threat posed by Iraq's weapons of mass destruction (WMD) were presented with a certainty that was not justified."
Chilcot said spy chiefs "should have made clear to Mr Blair that the assessed intelligence had not established 'beyond doubt' either that Iraq had continued to produce chemical and biological weapons, or that efforts to develop nuclear weapons continued".
But he was more cautious about the dossier on Iraq's weapons which was released by Blair's 10 Downing Street office in September 2002 and has become a focal point for criticism of the plan for war.
"There is no evidence that intelligence was improperly included in the dossier or that Number 10 improperly influenced the text," the report found.
"Despite explicit warnings, the consequences of the invasion were underestimated. The planning and preparation for Iraq after Saddam were wholly inadequate," the report said, referring to the ousted Iraqi dictator Saddam Hussein.
Blair "did not ensure that there was a flexible, realistic and fully resourced plan that integrated UK military and civilian contributions and addressed the known risks".
"The failures in the planning and preparations continued to have an effect after the invasion.
"The government's preparations failed to take account of the magnitude of the task of stabilising, administering and reconstructing Iraq."