Labour former cabinet minister David Blunkett has defended his backing of the Iraq war saying based on the information and context of the time he would have reached the same decision.
Lord Blunkett, who was home secretary in Tony Blair's government at the time of the 2003 invasion, said people had made decisions "on the basis of what they knew at the time".
He also warned against the "continually denigrating" of those who had done what they thought was in Britain's best interests.
The Labour peer was speaking during a debate in the House of Lords on the Chilcot report, which strongly criticised the way former prime minister Mr Blair took the country to war in 2003 on the basis of "flawed" intelligence with inadequate preparation at a time when Saddam Hussein did not pose an "imminent threat".
Sir John Chilcot also said the way the decision about the legal basis for the war was reached was "far from satisfactory", but the report did not rule on the legality of the military action.
Lord Blunkett argued the decision needed to be seen in the context of the time and that it "cannot be swept aside" that Saddam Hussein had used chemical weapons against his own people and in the war against Iran.
It was widely believed by the world that the Iraqi leader either had weapons of mass destruction or the ability to produce them, said Mr Blunkett.
He added: "It was in that context with the information that was available at the time, that some of us believed that the actions we were were moving to take were justified, albeit extremely painful and very often on a knife edge."
He also insisted there had been a debate about the right steps to take.
The information and decision-making structure had been "flawed", he acknowledged.
But Lord Blunkett added: "No structure would have in any way set aside the flawed intelligence and no structure would have changed the human nature of having to make decisions on that intelligence.
"This was not made in a vacuum. People were making decisions on the basis of what they knew at the time."
Lord Blunkett also did not believe the Syria conflict and resulting refugee crisis "had any roots back" to the decision back in 2003.
He said: "If I had the same information again, sitting in the same cabinet with the same context I would have made the same decision.
"And those who say they wouldn't, need to ask the question well what would it have been that changed their minds? Not hindsight."
While he said lessons needed to be learned he warned against "continually denigrating those who genuinely took a decision in what they believed to be in the best interests not just of the United Kingdom but the world as a whole".
Opening the debate, Defence Minister Earl Howe highlighted the thousands of lives lost in the conflict, including British troops.
It was in the memory of those killed and injured, that there was need "to do justice to the report's findings", he said.
Paying tribute to the service personnel who took part in the war, Lord Howe stressed the report was "most certainly not an indictment of their performance or their conduct".
He said the UK force had prosecuted a successful military campaign and helped remove Saddam Hussein who was "a brutal dictator who oppressed and murdered his own people".
Lord Howe added: "For all its present troubles Iraq is now a better, freer and more democratic country than it ever was under Saddam.
"Our armed forces can be proud they made a difference."
However, he said their efforts could "cannot disguise the shortcomings in decision-making and planning surrounding the operation and its aftermath that make Sir John's report such uncomfortable reading.
"While it may appear restrained, even quiet, in its approach its conclusions are stark and devastating."
While there were lessons to be learned, Lord Howe said many had already been addressed.
"We have not stood still waiting for Chilcot to be published," he told peers.
Lord Howe highlighted the setting up of the National Security Council aimed at ensuring joined up strategic decision-making at the top of government, and steps to tackle equipment failings.
The Ministry of Defence had also set up a team to review the report's findings and set out changes that needed to be made.
Lord Howe said one lesson that should not be drawn from the report was that intervention was always wrong.
"The challenge of the Government and the military in future is not simply to prevent bad intervention but to ensure better intervention when intervention is needed," he said.
Opposition defence spokesman Lord Touhig said he had voted to go to war in Iraq and said no one who had done so had taken it lightly.
He recognised the criticisms set out in the Chilcot report but pointed out it did not conclude the Government "acted in bad faith".
Lord Touhig described Saddam as a "murderous, evil tyrant" who had slaughtered tens of thousands of his own people and said it was believed he had the ability to produce chemical and biological weapons.
The Labour peer acknowledged the Iraq conflict had been divisive and contentious in the UK, but argued: "What it must not be allowed to do is to undermine our determination to protect British interests and our best interests by making us resolutely opposed to any interventions of any sort in the future.
"There will be times ahead when we will face a decision to intervene whether militarily or for humanitarian reasons.
"The Iraq conflict has left many painful scars on the body of our country but we mustn't, we cannot turn our back and fail to intervene where it is needed."
Liberal Democrat former leader Lord Campbell of Pittenweem said the Chilcot report had "vindicated" the stance of his predecessor Charles Kennedy, who had been accused of "appeasement" in his opposition to the 2003 invasion.
The peer said he had never believed they had been presented with a "false premise" for going to war, but that it was "flawed".
Mr Blair had made a moral judgment, said Lord Campbell and added: "But the strength of that judgment gave rise to the error of making the evidence fit that judgment rather than making the judgment fit the evidence."
Based on the evidence, the peer also felt it was "a legitimate judgment that this was not a legal war".
In the vacuum that followed the toppling of Saddam and the failure to have a plan, Lord Campbell said: "We became embroiled in a civil war. The welcome army of liberation became an army of hated occupation."
Former head of the civil service Lord Butler of Brockwell said it had been a mistake to use the ultimately flawed intelligence "as a means of political persuasion".
He added: "The Government was saying in effect 'don't just believe us, believe the intelligence'.
"As countless examples from history show intelligence is not uniquely worthy of belief it is uniquely worthy of scepticism."
Despite this, intelligence remained "crucial" he argued and said: "When we have weapons which can be directed to land on a sixpence it is all the more important to know which sixpence to direct them towards."
Lord Butler added that intelligence was "a very valuable, indeed indispensable aid to political military judgement but it is not a determinant".
He also said he had "considerable sympathy" for Mr Blair and had "never believed that he lied to the British people".
Lord Butler went on: "And I accept that he was sincere in believing that military action to remove Saddam Hussein was necessary as a last resort.
"The trouble was that he got caught in a trap in which a decision whether or not to join the Americans in military action became unavoidable before other means of containing Saddam had been exhausted."
With the Chilcot report painting a picture of a "dysfunctional" government, Lord Butler said: "Proper cabinet procedures should not be seen as pettifogging, bureaucratic impositions on busy ministers."
He added: "With hindsight the Blair government's disregard for the machinery of government looks not like modernisation but like irresponsibility.
"One of the lessons of the Chilcot report is that when the great responsibility of governing the country is accepted by ministers their main duty is good government of the people not personal political manoeuvring.
"If government is allowed to become a game of thrones it is the interests of the Government which will suffer.
"That lesson is going to be more important that ever in the difficult challenges which our government is now facing today."