The ex-UN commander in Bosnia General Sir Michael Rose said Mr Blair had to take responsibility for his actions.

"To go to war on what turns out to be false grounds is something that no one should be allowed to walk away from," he told BBC Radio 4's Today programme.

A Downing Street spokesman said Sir Michael was entitled to his view but had been retired for some time.

"The government is entitled to point out that there have been three democratic elections in Iraq," said the prime minister's official spokesman.

In a Channel 4 television documentary, Iraq: The Failure Of War, General Sir Michael tells former war correspondent and independent MP Martin Bell: "Blair should be impeached."

The general told Today the consequences for Iraq and the war on terror had been "quite disastrous".

The consequences of that war have been quite disastrous both for the people of Iraq and also for the west in terms of our wider interests in the war against global terror

General Sir Michael Rose

"Certainly from a soldier's perspective there can't be any more serious decision taken by a prime minister than declaring war," he said.

He claimed Mr Blair's actions were "somewhere in between" getting the politics wrong and acting illegally.

"The politics was wrong, that he rarely declared what his ultimate aims were, as far as we can see, in terms of harping continually on weapons of mass destruction when actually he probably had some other strategy in mind.

"And secondly, the consequences of that war have been quite disastrous both for the people of Iraq and also for the west in terms of our wider interests in the war against global terror."

The general said he believed MPs had endorsed the war because Mr Blair had stressed the argument about weapons of mass destruction.

General Sir Michael said he would not have led troops into a war he believed was wrong.

Commons motion

"You cannot put people in harm's way if you don't believe the cause is right or sufficient," he said.

But he added it would be wrong to just walk away from Iraq now.

There have been four separate inquiries into different aspects of the Iraq war, including the Butler report into intelligence failings and the Hutton inquiry into the death of Dr David Kelly.

But there has yet to be an inquiry focusing on the way the government's decision to join a US-led invasion was made.

This government, who are willing to lead us into a war, must also be willing to take responsibility for those actions

Plaid Cymru MP for Carmarthen East and Dinefwr, Adam Price

Last month, more than 100 MPs from across the Commons backed a call for an inquiry by senior MPs into the handling of the Iraq war and its aftermath.

The motion, proposed by Plaid Cymru MP for Carmarthen East and Dinefwr, Adam Price, called for a special committee of seven senior MPs to review the decision-making process.

The committee would be members of the Privy Council and therefore able to look at sensitive intelligence material.

On Monday, Mr Price said it was "essential a committee is established to investigate the matter thoroughly".

"If a government is not held to account for its actions, then democracy cannot be upheld.

"This government, who are willing to lead us into a war, must also be willing to take responsibility for those actions."