British Prime Minister Tony Blair told US President George W Bush eight months before the 2003 invasion of Iraq "I will be with you, whatever," and relied on flawed intelligence and unsatisfactory legal advice, a seven-year inquiry has concluded.
In a scathing critique of Mr Blair's leadership, the inquiry headed by John Chilcot said the threat posed by Iraqi dictator Saddam Hussein's supposed weapons of mass destruction had been over-hyped and the planning for the aftermath of war had been inadequate.
Protesters hold up a banner reading 'Blair must face war crimes trial' (Getty)
Unsatisfactory legal basis for war
John Chilcot, head of the inquiry, said in his statement: "We have concluded that the circumstances in which it was decided that there was a legal basis for UK military action were far from satisfactory."
The report cited several shortcomings in the legal process, including that the legal advice produced by the government's top lawyer was presented to a cabinet meeting of senior ministers, but not discussed in detail.
"There was little appetite to question Lord Goldsmith (Attorney General) about his advice" that the invasion was legal, and "no substantive discussion of the legal issues was recorded", the report said.
The report criticised the way Prime Minister Tony Blair presented intelligence information to the public: "The deliberate selection of a formulation which grounded the statement in what Mr Blair believed, rather than in the judgements which the JIC (Joint Intelligence Committee) had actually reached in its assessment of the intelligence, indicates a distinction between his beliefs and the JIC's actual judgements."
The intelligence itself was also criticised: "At no stage was the proposition that Iraq might no longer have chemical, biological or nuclear weapons or programmes identified and examined by either the JIC or the policy community."
Detail of a declassified handwritten letter sent by Tony Blair to George Bush (Reuters)
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."
Mr Blair was warned about the threat of increased al-Qaeda activity as a result of the invasion, the report said.
-"Mr Blair had been advised that an invasion of Iraq was expected to increase the threat to the UK and UK interests from al-Qaeda and its affiliates."
It cited Blair's response, made in a 2011 statement: "I took the view then and take the same view now that to have backed down because of the threat of terrorism would be completely wrong."
"The Iraq of 2009 certainly did not meet the UK's objectives as described in January 2003: it fell far short of strategic success. Although the borders of Iraq were the same as they had been in 2003, deep sectarian division threatened both stability and unity."
The report criticised the government's post-conflict planning for Iraq.
"The information on Iraq available to the UK government before the invasion provided a clear indication of the potential scale of the post-conflict task.
"When the invasion began, the UK Government was not in a position to conclude that satisfactory plans had been drawn up and preparations made to meet known post-conflict challenges and risks in Iraq and to mitigate the risk of strategic failure."
Demonstrators dressed as Tony Blair and George W Bush arrive with painted red hands and in hand cuffs outside the Queen Elizabeth II conference centre (Getty)
More than 13 years since the invasion, the war remains a deeply emotive issue for Britons. There are many who want Mr Blair to face criminal action over his decision to take the military action that led to the deaths of 179 British soldiers and more than 150,000 Iraqi civilians over the following six years.
Critics also say it fuelled a deep distrust in politicians and the ruling establishment. The report was issued 13 days after Britons delivered a stunning blow to their political leaders by voting to leave the European Union.
In a lengthy and passionate defence lasting almost two hours, Mr Blair justified his decision to back Bush and go to war alongside the United States in March 2003, at a time when the inquiry said peace options had not been exhausted and Saddam posed no imminent threat.
"I did not mislead this country. There were no lies, there was no deceit, there was no deception," the former Prime Minister told reporters, looking gaunt and strained but growing animated as he responded to questions.
"But there was a decision, and it was a controversial decision... to remove Saddam and to be with America. I believe I made the right decision and the world is better and safer as a result of it."
The only Labour Prime Minister to win three general elections, Mr Blair was in office for 10 years until 2007 and was hugely popular in his heyday, but Iraq has severely tarnished his reputation and legacy.
Families of slain British soldiers said they were considering whether to take legal action against him.
Mr Blair said he would take the same decisions again, and that he did not see that action as the cause of terrorism today, in the Middle East or elsewhere.
However, he acknowledged mistakes had been made.
"The intelligence assessments made at the time of going to war turned out to be wrong. The aftermath turned out to be more hostile, protracted and bloody than ever we imagined," he said.
"For all of this, I express more sorrow, regret and apology than you will ever know."
The inquiry report, running to 2.6 million words or more than four times the length of War and Peace, shed light on the interaction between Mr Blair and Mr Bush in the months leading up to the invasion, which has long been the subject of speculation about secret deals and pledges.
In a memo dated July 28, 2002, eight months before the invasion, Blair told Bush: "I will be with you, whatever. But this is the moment to assess bluntly the difficulties."
Outside the building where John Chilcot, the inquiry's chairman, delivered his findings, protesters chanted "Tony Blair, war criminal". But the report itself stopped short of saying the war was illegal.
"We have, however, concluded that the circumstances in which it was decided that there was a legal basis for military action were far from satisfactory," Mr Chilcot said.
Reg Keys, whose son, 20-year-old Lance Corporal Thomas Keys, was killed in Iraq, said: "We all know who the key players are... who took part in this most shambolic episode in British politics. We would like to see all those key players face some form of accountability."
He added: "If that's through the legal channels, then we will look at that and see what's viable and appropriate. It has been passed over to lawyers."
Mr Chilcot's report also said there was no imminent threat from Saddam at the time of the invasion in March 2003, and the chaos in Iraq and the region which followed should have been foreseen.
MPs who voted to support the invasion of Iraq need to take their share of responsibility for the mistakes that were made, current Prime Minister David Cameron says.
Mr Cameron said the country must ensure its armed forces are well-equipped for any future conflict.
"The decision to go to war came to a vote in this House and members on all sides who voted for military action will have to take our fair share of the responsibility," he told parliament on Wednesday.
"We cannot turn the clock back but we can ensure that lessons are learned and acted on.
"It is crucial to good decision-making that a Prime Minister establishes a climate in which it's safe for officials and other experts to challenge existing policy and question the views of ministers and the Prime Minister without fear or favour."
Cameron also told parliament that while the invasion of Iraq had created space for al-Qaeda, it was important to remember that violent Islamist extremism began long before the Iraq war.
"I think the most important thing we can do is to really learn the lessons for the future and the lessons he lays out quite clearly," he said, referring to the Chilcot report.
"The only point I would make is that there is actually no set of arrangements and plans that can provide perfection in any of these cases.
"Military intervention is always difficult, planning for the aftermath of intervention, that is always difficult and I don't think in this House we should be naive in any way that there's a perfect set of plans... that can solve these problems in perpetuity."
He also said Britain's military involvement in Afghanistan had not repeated the planning failures of the 2003 Iraq invasion.
"I don't accept that all the same failures are apparent in some way when it comes to planning in Afghanistan.
"In Afghanistan, there was a very clear connection between a Taliban regime which was playing host to al-Qaeda," he said.
"The goal of government policy, which I supported at the time and indeed put into place when I became Prime Minister, was to make sure that country couldn't become a safe haven for al-Qaeda, and there was some considerable success in pursuing that."
Britain was involved in the conflict in Afghanistan between 2001 and 2014.
Mr Cameron also emphasised the importance of Britain's relationship with the US after opposition Labour leader Jeremy Corbyn said Britain needed to have a more open and independent relationship with the US after the report showed Britain joined the war without satisfactory legal basis or proper planning.
"I don't believe the United States is always right about everything but I do believe our partnership with the United States is vital for our national security," Mr Cameron told parliament. "They are always our best partner and we should work with them."
Reuters / Newshub.