A defiant Tony Blair mounted a vigorous defence of the invasion of Iraq, insisting he had no regrets over removing Saddam Hussein and would do the same again.

In his long-awaited appearance before the Iraq Inquiry, the former prime minister denied he had taken the country to war on the basis of a "lie" over Saddam Hussein's supposed weapons of mass destruction (WMD).

He suggested the world could now be faced with the threat of a nuclear-armed Iraq if he and President George Bush had not taken action to confront the Iraqi dictator.

Asked at the end of six hours of testimony on Friday by inquiry chairman, Sir John Chilcot, whether he had any regrets, he said: "Responsibility but not a regret for removing Saddam Hussein.

"I think that he was a monster. I believe he threatened not just the region but the world. And in the circumstances that we faced then, but I think even if you look back now, it was better to deal with this threat, to remove him from office."

One member of the audience shouted out: "What, no regrets? Come on".

Then as he left, another audience member heckled: "You are a liar," while another added, "And a murderer".

His voice apparently beginning to fade, after what had been a largely assured and fluent performance, he insisted that Britain - and in particular the armed forces - should feel an "immense sense of pride" for the role they had played.

"I had to take this decision as prime minister. It was a huge responsibility and there is not a single day that passes by that I don't reflect and think about that responsibility and so I should," he said.

"But I genuinely believe that if we had left Saddam in power, even with what we know now, we would still have had to have dealt with him, possibly in circumstances where the threat was worse.

"In the end it was divisive and I am sorry about that and I did my level best to bring people back together again but if I am asked whether I believe we are safer more secure, that Iraq is better, that our own security is better, with Saddam and his two sons out of office and out of power, I believe indeed we are."

The former prime minister earlier told the inquiry that the UK's policy up to the September 11 terror attacks was one of "containment".

But he said that following the atrocity, his view "changed dramatically".

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