Mr Blair has always insisted that invading Iraq was the right thing to do
Tony Blair has told the BBC it would have been right to remove Iraqi leader Saddam Hussein from power even without evidence that he had weapons of mass destruction (WMD).
It is the latest in a long line of statements the former prime minister has given on the March 2003 invasion.
BBC News looks back at how the rhetoric has changed over time.
10 April 2002
Some 11 months before war began, and with the fallout from 9/11 still dominating the political agenda, Mr Blair told the House of Commons: "Saddam Hussein's regime is despicable,
he is developing weapons of mass destruction,
and we cannot leave him doing so unchecked.
"He is a threat to his own people and to the region and, if allowed to develop these weapons, a threat to us also."
24 September 2002
Later that year, Mr Blair made what came to be an infamous claim to MPs: "It [the intelligence service] concludes that Iraq has chemical and biological weapons, that Saddam has continued to produce them, that he has existing and active military plans for the use of chemical and biological weapons, which
could be activated within 45 minutes."
4 June 2003
Nearly three months after the invasion, no WMDs had been uncovered, but Mr Blair said he had
that inspectors would "find the clearest possible evidence of Saddam's weapons of mass destruction".
8 July 2003
Pressure was mounting as searches in Iraq continued to draw a blank, but under cross-examination by the Commons Liaison Committee, the then PM insisted:
"I don't concede it at all that the intelligence at the time was wrong."
16 December 2003
A few months later his tone had softened slightly in an interview with the BBC Arabic Service, as he said: "I don't think it's surprising we will have to look for them."
11 January 2004
By early 2004, in an interview with BBC Breakfast with Frost, Mr Blair showed his first real doubts. Asked whether he was wrong about WMD, he said: "I don't know.
"The chief of defence staff and other people were saying, 'Well, we think we might have potential WMD finds here or there'. Now
these things didn't actually come to anything
in the end."
28 January 2004
As time went on, Mr Blair was forced to deny he had deceived the public: "The allegation that I or anyone else lied to this House or deliberately misled the country by falsifying intelligence on WMD is itself the real lie."
6 July 2004
Further evidence of his contrition on the issue of weapons came in evidence to the Commons Liaison Committee:
"We don't know what has happened to them.
They could have been removed. They could have been hidden. They could have been destroyed."
14 July 2004
Later the same month, during the Butler inquiry into the invasion, Mr Blair admitted: "We expected, I expected, to find actual usable, chemical or biological weapons after we entered Iraq.
"But I have to accept, as the months have passed, it seems increasingly clear that at the time of invasion,
Saddam did not have stockpiles of chemical or biological weapons
ready to deploy."
28 September 2004
That year's keynote Labour conference speech brought a genuine change of direction. Mr Blair not only conceded that intelligence was incorrect, but also offered regime change as a worthy justification for war nonetheless.
"I can apologise for the information being wrong but I can never apologise, sincerely at least, for removing Saddam.
The world is a better place with Saddam in prison
not in power."
7 October 2004
The chief US weapons inspector in Iraq Charles Duelfer concluded that there had been no stockpiles of biological, chemical or nuclear weapons before the invasion.
But Mr Blair still interpreted the report as proof that Saddam had "every intention" to develop WMD.
1 May 2005
A leaked memo suggested that Mr Blair was looking at ways to justify war with Iraq in July 2002, but he told the BBC that was wrong - despite his previous claims that regime change was morally right.
"If the UN resolution had been adhered to by Saddam that would have been the end of it, despite the fact it was the most appalling regime," he said.
21 March 2006
A speech on foreign policy in London sounded the final death knell for WMDs.
Mr Blair did not mention weapons once, but said the invasion was part of a wider global struggle between "democracy and violence".
"This is not a clash between civilisations.
It is a clash about civilisation,"
17 Nov 2007
Those words were reinforced in an interview the following year with the Times: "Whatever it began as, it is part of this wider struggle today and... if there's anything I regret... it is... not having laid out for people in a clearer way what I saw as the profound nature of this struggle and the fact that it was going to go on for a generation."
But he added: "I believed in it. I believed in it then, I believe in it now."
12 December 2009
In an interview with Fern Britton for the BBC, Mr Blair said a lack of WMD would not have saved Saddam:
I would still have thought it right to remove him.
"I mean obviously you would have had to use and deploy different arguments about the nature of the threat."
He said the "notion" of Saddam as a threat was what mattered, and one aspect of that was "the development of WMD".