In his response to the publication of the inquiry into the Iraq War, Blair argued he had to be a "decision maker" as the country's leader and that in his judgment the world is today "a better place without Saddam Hussein".
Tony Blair said he understood why some families of service personnel killed in Iraq "can never forgive me" as he continued to defend his actions following the damning report by Sir John Chilcot into the war.
He also said that the legal basis for British military action in Iraq was "far from satisfactory", stressing that British policy on Iraq was made on the basis of "flawed intelligence and assessments".
In a December 2001 memo, among more than 30 such notes released with the Chilcot report, Mr Blair said to Mr Bush that he would be "with you, whatever", before setting out some of the conditions he believed the United States would need to meet to attract support, including seeking UN authorisation.
He added: "There may be people who believe that until I say I took the wrong decision, I am not properly sorry".
Relatives of some of the British soldiers who died in Iraq said they would study the report to examine if there was a legal case to pursue against those responsible.
Australian Independent MP Andrew Wilkie, a former intelligence analyst, said Saddam Hussein then posed no imminent threat and asked that both Howard and the former Foreign Minister Alexander Downer should be held accountable for Australia's participation in the Iraq war. They say "no we want you to apologise for the decision".
In a statement which was twice as long as that delivered by Chilcot, Blair sought to address the full spectrum of criticism leveled at him, saying he accepted total responsibility "without exception or excuse". "I made the decision in good faith on the information that I had at the time".
However, Chilcot said military action "might have been necessary at some point".
Premeditated: It revealed he'd agreed to invade Iraq at least eight months before getting backing from the UK Parliament, when he told US President George W Bush "I will be with you, whatever".
This failure of intelligence has always been at the centre of Iraq war criticisms.
Mr Blair said that there are some big questions going forward for the political leadership, and also for the Armed Forces, as to what Britain's role in the world should be.
"It was the last moment of decision for us", Mr Blair said.
In his first interview after the inquiry was published, Blair said that "no decision to go to war had been taken" after a key piece of evidence showed a memo from Blair to President George W. Bush that began "I will be with you, whatever".