Jeremy Corbyn has apologised on behalf of Labour for Tony Blair's decision to go to war in Iraq, saying it was a "stain" on the party and country, after the former Prime Minister insisted he stood by his actions.
The current Labour leader's comments came after a meeting with the families of some of the victims of the 2003 conflict and the occupation that followed, after the unveiling of the 2.6 million-word Chilcot report into the UK's most controversial military engagement since the end of the Second World War.
With his voice breaking at an emotional news conference that lasted almost two hours, Mr Blair expressed his "sorrow, regret and apology" for the "failures" over Iraq, but insisted he stood by his actions - and would make the same decision again.
Mr Blair said he expresses "more regret, sorrow and apology than you can ever know or can believe".
But anti-war Mr Corbyn used his speech to go a step further, as he apologised to the people of Iraq, the families of soldiers who were killed or wounded and the British public.
In a speech in London, he said: "The decision to go to war in Iraq has been a stain on our party and our country but we now have the chance to work together to build more constructive and mutually beneficial relationships with the rest of the world based on cooperation, peace and international justice."
Mr Blair earlier said he firmly believed he had done the "right thing" and that the world was a "better place" without Saddam Hussein, adding the decision to remove the dictator was the "hardest, most momentous, most agonising" of his 10 years in office.
And he insisted he would make the same decision again today if he was presented with the same information..
"If I was back in the same place, with the same information I would take the same decision because obviously that was the decision I believe was right," he said. "All I’m saying today, because obviously some of the intelligence has turned out to be wrong, the planning wasn’t done properly, I have to accept those criticisims, I accept responsibility for them."
The long-awaited official report into Britain's involvement in the Iraq war delivered a scathing verdict on Government ministers' justification, planning and conduct of a military intervention which "went badly wrong, with consequences to this day".
Mr Blair presented the case for war in 2003 with "a certainty which was not justified" based on "flawed" intelligence about the country's supposed weapons of mass destruction (WMD) that was not challenged as it should have been, found report author Sir John Chilcot after his seven-year inquiry.
Mr Blair acknowledged that some of the families of the 179 British personnel killed in the conflict could "never forget or forgive" him for what happened.
While Mr Blair accepted the report contained "serious criticisms", he said it showed Parliament was not misled, there was no secret commitment to war, intelligence was not falsified and the decision was made in "good faith".
"A decision had to be taken and it was for me to take as prime minister. I took it, I accept full responsibility for it, I stand by it," he said, his voice close to breaking.
"I only ask with humility that the British people accept that I took this decision because I believed that it was the right thing to do based on the information that I had and the threat I perceived and that my duty as prime minister at that moment in time was to do what I thought was right.
"At moments of crisis such as this it is the profound obligation of the person leading the government of our country to take responsibility and decide. Not to hide behind politics, expediency or even emotion but to recognise that it is the privilege above all others to lead this nation.
"But the accompaniment of that privilege when the interests of our nation are so supremely and plainly at stake is to lead and not to shy away, to decide and not to avoid decision, to discharge that responsibility and not to duck it."
Families of some of the military personnel killed in Iraq branded the former prime minister a "terrorist", while Labour leader Jeremy Corbyn said Sir John's long-awaited report made clear that Parliament was misled and the invasion was "an act of military aggression based on a false pretext".
Unveiling his report into the UK's most controversial military engagement since the end of the Second World War, Iraq Inquiry chairman Sir John said the war "went badly wrong, with consequences to this day".
He made no judgment on whether military action was legal, but found that then attorney general Lord Goldsmith's decision that there was a legal basis for UK involvement in the US-led invasion was taken in a way which was "far from satisfactory".
Key findings in the long-delayed report included:
-* The case for war was presented with "a certainty which was not justified";
-* It was based on "flawed" intelligence about the country's supposed weapons of mass destruction (WMD) which was not challenged as it should have been;
-* The use of force to remove dictator Saddam Hussein was undertaken at a time when he posed "no imminent threat" and in a way which undermined the authority of the United Nations Security Council;
-* Planning for post-conflict Iraq was "wholly inadequate", with shortfalls in armoured vehicles to protect UK troops which "should not have been tolerated"
The report did not support claims that Mr Blair agreed a deal "signed in blood" to topple Saddam at a key meeting with George Bush at his ranch in Crawford, Texas, in 2002.
But it revealed that in July that year - eight months before Parliament approved military action - the PM committed himself in writing to backing the US president over Iraq, telling him: "I will be with you whatever."
Former US president George W Bush has backed the arguments of Tony Blair in defence of their decision to invade Iraq in 2003.
Mr Bush insisted the world is better off without despotic Iraqi president Saddam Hussein in power and said "there was no stronger ally" than Britain when Mr Blair was prime minister.
Mr Blair was severely criticised by Sir John Chilcot's inquiry into the Iraq War, with his closeness to Mr Bush and his July 2002 assurance that he would back the US commander in chief "whatever" coming under particular scrutiny.
Mr Bush's communications director, Freddy Ford, told BBC News: "President Bush is hosting wounded warriors at his ranch today and has not had the chance to read the Chilcot Report.
"Despite the intelligence failures and other mistakes he has acknowledged previously, President Bush continues to believe the whole world is better off without Saddam Hussein in power.
"He is deeply grateful for the service and sacrifice of American and coalition forces in the war on terror. And there was no stronger ally than the United Kingdom under the leadership of Prime Minister Tony Blair.
"President Bush believes we must now find the unity and resolve to stay on the offensive and defeat radical extremism wherever it exists."
5:57pm
Father of soldier who died in Iraq challenges Blair to meet him
Peter Brierley, whose son Shaun died during the conflict, was among those who had a private meeting with Mr Corbyn and heard his public apology.
He said: "It's something I would have expected from Jeremy - he's always been anti-war.
"For him to be able to stand up there and give us that apology - it means more than if the right bloke had done it.
"He is under fire, he did not have to do that."
Mr Brierley said it was right that Mr Corbyn did not attack Mr Blair in his speech, adding: "That is not what he was there for. He was talking about the Chilcot Report and what happened in Iraq and he did not mention legalities and he didn't mention people who did wrong."
But the 65-year-old, from Batley, West Yorkshire, challenged the former prime minister to a face-to-face meeting to explain his decision.
"I know that he does not want to face us - he seems to be frightened in our presence," he said.