Former British prime minister Tony Blair said he had no regrets about the 2003 US-led invasion of Iraq, saying Saddam Hussein was a threat to the world who had to be disarmed or removed.

Blair said the September 11 Al Qaeda attacks on the US meant rogue states had to be dealt with to prevent weapons of mass destruction (WMD) falling into the wrong hands, risking even greater carnage.

Facing the first official public grilling on why he sent 45,000 British troops to war in Iraq, he repeatedly said he was concerned that such a risk remained today, referring to fears over Iran's disputed nuclear programme.

"Responsibility, but not a regret for removing Saddam Hussein," he said, when asked if he had misgivings about taking military action. He said a majority of Iraqis would say they were better off now than under the former dictator.

The decision to go to war was the most controversial episode of Blair's 10-year premiership, provoking huge protests, divisions within his Labour Party and accusations he had deceived the public about the reasons for invasion.

"In the end it was divisive. And I'm sorry about that," he said. "But if I'm asked if 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 power and out of office, then I believe indeed we are.

Judgment call

During six hours of intense questioning, Blair, 56, was unrepentant over the stand he took with then US President George W Bush, batting away queries about the legality of war or whether he had misled the public over the reasons for it.

"This isn't about a lie, or a conspiracy, or a deceit, or a deception, this is a decision," said Blair, who initially looked nervous but grew more assured as the hearing went on.

The inquiry is seeking to learn the lessons from the conflict and does not have the power to punish individuals.

Saddam's history of using WMD and his refusal to cooperate with UN inspectors meant he posed a threat that could not be ignored, Blair said.

No evidence has emerged to link Iraq with the September 11, 2001 attacks on the United States, but Blair said they had changed the "calculus of risk".

"I believed ... we were right not to run that risk," said Blair, adding he was convinced Saddam was intent on restarting his WMD programme and had retained the intellectual know-how to do so, even though no such weapons have ever been found.

The Iraq war sapped support for Blair and his Labour Party and the issue provokes deep public anger almost three years after Blair handed over to Gordon Brown.

Brown will appear in late February or early March and commentators say the inquiry could damage Labour before an election due by June, with the party trailing in opinion polls after 13 years in power.

Exaggerated intelligence?

Critics have long argued that Blair promised Bush in April 2002 that Britain would support military action to get rid of Saddam, and then exaggerated intelligence about WMD.

"The only commitment I gave, and gave openly, was a commitment to deal with Saddam," he said. "If we tried the UN route and that failed, my view was it had to be dealt with."

Blair defended the war's legality, relying on the green light the government's top lawyer gave only days before the conflict, and said a second UN resolution had only been desirable from a political, not legal perspective.

But he admitted post-war planning had been flawed.

"The planning assumption that ... everybody made was that there would be a functioning civil service. Contrary to what we thought ... we found a completely broken system," he said.

"People did not think that al Qaeda and Iran would play the role that they did. It was the introduction of the external elements of AQ and Iran that really caused this mission very nearly to fail. Fortunately in the end it didn't."

Protesters, including relatives of some of the 179 British soldiers killed in Iraq, demonstrated outside the inquiry venue opposite parliament, accusing Blair of being a war criminal.

"He's a consummate politician and he spoke as a politician," said Roger Bacon, whose son Major Matthew Bacon was killed in Basra in 2005.

"When we do find ourselves in a situation where we have to go into conflict again, we are better prepared for it so I don't think it'll be a whitewash." – Reuters