Tony Blair has cause to celebrate, but the charges against him still stand

After the war against Iraq, evidence of a programme to develop weapons of mass destruction has come to light - but in a different country. Clearly, Libya has been building up its military might with greater success than Saddam Hussein. Now the country seeks a new international standing - without the prospect of any intimidating weapons at all.

The reasons for Colonel Gaddafi's welcome conversion from tyrant to international statesman are complex and varied. That tends to be the case when conversions are made on such a big scale. On Friday night, Tony Blair revealed that Libyan representatives came to Britain in March, following the "successful negotiations on Lockerbie, to see if it could resolve its WMD issue in a similarly co-operative manner". This statement can be read in two ways. The precise timing of the initiative coincided with the war against Iraq. Implicitly, Blair links his triumph over Libya with the attack on Iraq. Yet his references to the earlier successful resolution of the controversies raging over Lockerbie suggest that Gaddafi had become more pragmatic long before the US and Britain decided to attack Iraq. Some Foreign Office insiders, who claim that the negotiations with a reformed Gaddafi began five years ago, confirm the suggestion.

For good reason, the Prime Minister and senior ministers are being restrained about linking Libya's voluntary disarmament to the war against Iraq. They are happy to hint at the connection, but do not want to humiliate Gaddafi by implying he is acting solely to avoid the dark fate of Saddam. Some non-ministerial supporters of the war will be less constrained, arguing that the capture of Saddam and Gaddafi's contrition add up to a triumphant vindication of the Bush-Blair strategy: a turbulent Middle East is being transformed by force, the threat of force and big, sumptuous carrots for those who begin to behave themselves. Prepare to look at the carrots that will be rightly dangled in front of a newly restrained Gaddafi over the next few months.

The supporters of the war should not get too carried away by this new ammunition. The region remains a tinderbox even without the destructive menace previously posed by Gaddafi. Indeed, one of the revelations from Friday was the degree to which Libya had been re-arming. In the space of a few minutes, we discovered that it had been ready to become a nuclear threat, but that it was no longer one because it was intending to disarm. To some extent, the first revelation cancelled out the second. On one level we are back to where we were before Blair delivered his astonishing words. Parts of Iraq are unstable, along with the neighbouring states, which are unlikely to be willing to hand over their weapons in quite the same way as Gaddafi has been. Above all, there is the inflammatory anomaly of Israel, which is building up its weapons of mass destruction, with President Bush choosing to take no notice.

Sometimes a dramatic event has no wider context - and might well have norepercussions, either. This is the case with Libya. Forget about the war against Iraq and celebrate the willingness of one tyrant to change. Celebrate also the diplomatic persistence of the Government. Blair is good at this. He saw an opportunity with Libya and took it. It is extraordinary that no hint of the talks leaked out - a tribute to the high seriousness of those involved. Nor am I suspicious about the timing of the announcement, coming as it does at the end of a turbulent year. There have been plenty of times in recent months when Blair could have done with good news - not least over the Hutton-dominated summer and on the eve of the Labour Party conference.

Whether it will change his political fortunes is another matter. He did not go to war against Iraq in order to uncover weapons in Libya. Nor did he attack Baghdad to capture Saddam, although this was a highly welcome development. He went to war on the precise claim that Iraq posed an imminent threat because it possessed WMD. I cannot see how the fact that Gaddafi has confessed to possessing a programme to develop them justifies the earlier argument about Iraq, especially as it was a claim made with such persistent passion in dossiers, press conferences, TV interviews and statements in the Commons. This remains Blair's great political problem, which has been made more acute by Robin Cook's diaries. The former Leader of the House suggests that Blair knew on the eve of war that Saddam had ceased to pose an imminent threat. We know, too, from the Hutton inquiry that the Prime Minister's senior adviser, Jonathan Powell, wondered openly whether Iraq was the threat that the Government was claiming it was.

Lord Hutton will be giving his verdict next month. It has become a journalistic cliché to suggest that, as a result, Blair faces a possibly fatal January. I predict that he will get off lightly. Lord Hutton has a limited remit, which is to examine the events leading up to the death of Dr David Kelly. He will not be giving his judgment on how, and why, Britain went to war. During his hearing he recalled some witnesses for a second time. He suggested that they risked coming in for criticism and, therefore, he sought clarification from them. Blair was not one of those who were summoned for a second interrogation, suggesting that Lord Hutton was satisfied with his account. More broadly, how can one judge decide whether a prime minister, or anyone else, is responsible for a suicide? The peculiar nature of Lord Hutton's brief demands measured language, even for those singled out for criticism. His report will be less troublesome for Blair than the vote in the Commons on top-up fees. The Prime Minister will probably win the vote, but only by making concessions that render the policy virtually meaningless.

That is for January. Blair's year ends with genuinely good news, but in the context of the war against Iraq it is the wrong type of good news. The discovery of a cruise missile or two in Iraq would have been the right type, an affirmation at least of his pre-war position. Instead, the senior weapons inspectors appear to be on the point of packing their bags in Iraq, leaving the country empty-handed. Suddenly, almost comically, the disarmament of Libya becomes a reason why Britain went to war against Iraq. The Prime Minister will be tirelessly attentive over Libya, just as he must have been behind the scenes in recent months. When the opportunities for peaceful outcomes arise he makes the most of them.

The exception was Iraq when Blair chose to go to war. Despite his diplomatic triumph in Libya and the prospect of a tame indictment from Lord Hutton, he is still charged with taking Britain into a conflict on a false premise. There is no more serious charge a prime minister can face.