The prime minister has defended his decision to go to war against Saddam Hussein.

Tony Blair told MPs on Tuesday that he did not regret invading Iraq.

The prime minister told the Commons liaison committee that he accepted large stockpiles of weapons were unlikely to be found.

But he said it had been right to topple Saddam Hussein's regime.

"No I do not regret it. Neither do I regret the action that we took," he told foreign affairs committee chairman Donald Anderson.

"I do not believe it was wrong to remove Saddam Hussein. I have no doubt whatsoever that we did the right thing."

Blair argued that invading Iraq was vital to the war on terrorism as sections of the regime could have sold chemical or biological weapons to groups such as al Qaeda.

"If we hadn't have acted in Iraq we wouldn't have had a hope in dealing with this issue," he said.

"This threat of the interaction of unstable, chaotic states with weapons of mass destruction and terrorism is the security threat of the 21st Century."

Inquiry

Number 10 has also confirmed that the government will hold an inquiry into the "perfectly valid" questions over the intelligence on Iraq’s deadly weapons arsenal.

Blair accepted there was a need to review the issue.

"I think there are issues to do with intelligence, to do with intelligence gathering and evaluation and use by government which we can look at," he said.

"But the issue of good faith was determined by the Hutton inquiry and I really think it is incumbent upon people to accept that."

The revelation follows President Bush's decision to hold an inquiry into intelligence on Iraq.

Blair rejected the claim by Sir George Young that the government had been caught out by the Bush administration.

"First of all, it did not take us by surprise. We have been working very closely with the Americans," he said.

But he rejected the idea that the new investigation would amount to the sweeping judicial review being demanded by his political rivals.

"We must not have a re-run of the Hutton inquiry. That would be completely absurd," Blair said.

Iraq WMD survey

Blair tackled head-on the comments by the chief of the Iraq survey group David Kay that weapons were unlikely to be found in large quantities.

"What is untrue is to say that he was saying there was no weapons of mass destruction programme or capability and that Saddam was not a threat," the prime minister said.

"He actually believes that Iraq was possibly a more dangerous place than we had thought, that the conflict was justified and that if we had refused to go to conflict, then the security of the world would be put at risk."

Intelligence rules

Referring to Dr David Kelly, he said it was wrong that the scientist had met with journalists and that he was considering formal guidelines for the security services.

"Let's be under no doubt about this at all - we cannot have a situation where we simply treat intelligence or security advice that is given in a way that we just throw it open to whoever wants to pick it up," he said.

"Our intelligence services in this country do a good job. They do an immensely difficult job.

"And intelligence is not some absolute science, as we all know."

Review of powers

Giving evidence to MPs Blair also backed calls for a review of Commons committee powers following the Hutton probe.

He said he was in favour of changing the rules over witnesses and evidence following the law lord's inquiry.

Committee chairmen had highlighted the fact that Lord Hutton had been given unprecedented access to witnesses and evidence from within government and the security services.

"We're very happy to do that and look at the lessons we can learn from Hutton," Blair said. "It was remarkable in terms of openness."