The Prime Minister led us into an illegal war

UK policy changed from containing Saddam's regime to changing it - only no one could be told

Yesterday, at Prime Minister's Questions, I challenged the Prime Minister to admit that he "led us into an illegal war". I said that we now know that the 45-minute claim was unfounded; that there were no weapons of mass destruction in Iraq; and that regime change - which is contrary to international law - was the only remaining argument.

Yesterday, at Prime Minister's Questions, I challenged the Prime Minister to admit that he "led us into an illegal war". I said that we now know that the 45-minute claim was unfounded; that there were no weapons of mass destruction in Iraq; and that regime change - which is contrary to international law - was the only remaining argument.

The Prime Minister blustered and was angry. But so was I. This war was wrong and it's time he faced up to it. For those of us who care about the way this country is run, and have a duty to hold the government to account, it's necessary to keep pursuing the truth about how we got involved in the worst foreign policy disaster since Suez.

This week's report from the Iraq Survey Group - which shows there were no weapons of mass destruction or active programmes - makes it clear that Saddam was a medium-term threat, but not one so immediate and serious that war was the only option. "Intent" is not an option under the UN Charter.

Meanwhile, documents leaked last month suggest that the WMD threat was also basically spin - a way of selling the war while the Government was actually embarked on a policy of regime change. This is a matter of considerable significance: not least because regime change is illegal. When was that decision taken and how? The likely date for this policy change was a summit with President Bush in Crawford, Texas in April 2002 - a whole year before war began and seven months after 11 September.

The papers show that the Prime Minister was being made aware of the risks. The Foreign Office legal team was reminding him regime change was illegal. So was the Foreign Secretary himself. Writing to the Prime Minister, Jack Straw refers to it as "the elephant trap" adding that "regime change could form part of the method of any strategy, but not the goal".

Tony Blair arrived in Washington aware that for the neo-conservatives around George Bush, Saddam Hussein was a priority target.

The leaked documents give a clear indication what the Prime Minister was thinking. His foreign policy adviser, Sir David Manning, told Condoleezza Rice, the US National Security Adviser, in March 2002 that the Prime Minister "would not budge in your support for regime change". So British officials at the highest level, were already talking to their US counterparts about a war based on regime change - even before their bosses had sat and talked.

Of course, a conversation between officials isn't the same as the real thing between the leaders. And the truth is that we just don't know exactly what happened when the Prime Minister and the President met face to face. Was that the moment when Tony Blair committed British forces to war if it came to an invasion? The evidence points that way.

But he kept it quiet. He didn't have to. He had ample opportunity to be "open". Standing beside President Bush outside the Crawford Ranch, Tony Blair was asked a direct question about regime change. "A matter for discussion," he said. A week later, in the House of Commons, he ducked the same straight question.

It's quite a peculiar situation. UK policy had changed from containing Saddam's regime to changing it. Only no one could be told. Tony Blair didn't inform Parliament of this change in policy - or even his own Cabinet, according to former minister Robin Cook.

And Sir David Manning, writing before the summit, spells out the dilemma. The problem, he had said, was how to sell this change in policy to the British people, its press and Parliament. The plan had to be "clever".

What followed were the dodgy dossier on Weapons of Mass Destruction and the exaggeration and misrepresentation of patchy intelligence as "extensive, detailed and authoritative". That explains why, when the "war of liberation" turned into an unpopular occupation and no WMDs were found, the Prime Minister went to great lengths to prevent the open inquiry my party repeatedly sought into what had gone wrong. The last thing No 10 could afford was proper scrutiny of the actions of the politicians themselves and the advice given to ministers.

Some might say this is just the usual stuff of government - covering its back. Yet the Prime Minister told me in the House of Commons that the kind of inquiry I sought would be "undemocratic". But today, it is precisely the damage which has been done to democratic responsibility and which continues to erode public trust in the political process, which drives me forward to look for answers.

The fact is that Prime Ministerial power was allowed to progress without sufficient checks and balances. Parliament was sidelined, the Select Committees muted, while collective Cabinet government was a joke.

It's time the country got some straight answers, time the Prime Minister told us what was really going on in those fatal months before the war began; not least because there are further international crises looming. The Bush administration appears to have its sights set on Iran. We need to be able to trust Tony Blair's judgement.

The writer is leader of the Liberal Democrat Party