"We have concluded that the UK chose to join the invasion of Iraq before the peaceful options for disarmament had been exhausted. Military action at that time was not a last resort," John Chilcot, the chairman of the official inquiry into the war set up in 2009.
The UK did not exhaust all peaceful options before joining the invasion of Iraq, the former senior civil servant said.
His 12-volume, 2.6-million-word report on the Iraq war comes over seven years after the inquiry was ordered by then prime minister Gordon Brown in 2009.
Reacting to the report, Blair claimed it absolves him of any "lies or deceit" even as he expressed "sorrow and regret" for the 180 British soldiers were killed in the war from 2003 to 2009.
The Labour party stalwart, 63, who was in charge when the UK joined US forces to invade Iraq in 2003, said he will take "full responsibility" for any mistakes made but stressed that Chilcot's 'Iraq Inquiry' makes clear there was no "falsification or improper use of intelligence".
Delivering a crushing verdict on Blair who was prime minister when the UK decided to go to war alongside the US to unseat Hussein as president of Iraq, Chilcot said, "When the potential for military action arises, the government should not commit to a firm political objective before it is clear it can be achieved. Regular reassessment is essential.
Chilcot's long-overdue report spans almost a decade of UK government policy decisions between 2001 and 2009.
It covers the background to the decision to go to war, whether troops were properly prepared, how the conflict was conducted and what planning there was for its aftermath, a period in which there was intense sectarian violence.
