The dangers of crying wolf

The trouble with not possessing a reverse gear is that the only way to perform a U-turn is with a violent yank on the handbrake. There is a terrific smell of burnt rubber coming off Tony Blair.

First, it was the transformation of Ken Livingstone from zero in the Prime Minister's estimation to hero. Now, and much more seriously, it is Iraq. After months of resistance, the Prime Minister has finally been forced to make a partial surrender to the clamour for an inquiry into the intelligence that he used to make the case for toppling Saddam.

Never mind a week being a long time in politics. A mere 48 hours can feel like an infinity in the life of this Government. One day Tony Blair is finished, the next day he is exonerated. One day he is triumphantly resurgent, the next day he is again on the back foot. One day, there's absolutely no need for another inquiry into Iraq. The next day, nothing could be more important.

As so often before in the Iraq saga, events in Washington have dictated the pace to Mr Blair. The decisive intervention came from Dr David Kay, the man hand-picked by the White House to search for those damned elusive weapons of mass destruction. The Prime Minister is entitled to maintain, as he did yesterday, that Dr Kay did report to a congressional inquiry that his team had uncovered evidence that Saddam Hussein was continuing to pursue clandestine chemical and biological programmes. Further, that the Iraqi dictator had never given up on his lust to acquire nukes.

Stockpiles of weapons of mass destruction may not have turned up in Iraq, and no one serious now expects any to be found, but that Saddam had an appetite for WMD was not just a figment of over-fevered imaginations in Number 10 and the White House. Nor was it simply a fabrication to serve other agendas.

The problem for both President and Prime Minister is that they made a case for war around not Saddam's WMD ambitions, but his actual capacity. So the observation by Dr Kay that rightly lit up the headlines was his conclusion that the intelligence agencies were probably "all wrong" about that, a wrongness then compounded by the hardening up of often fragmentary and qualified intelligence product for public consumption.

Once George Bush had condulyceded an inquiry - albeit one conveniently timed to report after the American presidential election in November - Mr Blair would have looked as ridiculous as he would have looked isolated if he had not done something similar.

It provides the Prime Minister with a new blocking line, at least until Lord Butler reports in the summer. Instead of telling everyone to be patient until the final conclusions of the Iraq Survey Group, Mr Blair and other ministers will now tell us to wait for the findings of the Butler Inquiry.

Whatever this brings to light, I'm doubtful whether terribly many people's minds will be changed by this inquiry, any more than they have been by the three inquiries that we've already had. Tony Blair will go to his grave believing that removing a vicious tyrant was the "right thing to do" which "has made the world a safer and better place". He will forever insist, as he did before MPs yesterday, that "we should be proud of what we did". Those who support his moral argument for removing Saddam will continue do so.

Those who believe that Iraq was illegally invaded on a false prospectus aren't likely to be budged from that conviction either. Certainly not by an inquiry with a cast list that ticks every Establishment box. The chairman is a former Cabinet Secretary. The two MPs, one a former Northern Ireland minister, another an ex-Chief Whip, both supported the war. They are joined by a former Chief of the Defence Staff and a former Permanent Secretary at the Northern Ireland Office.

That line-up from the top drawer, along with the pretty inevitable fact that they will take evidence in secret, has provoked instant predictionsof a fix-up. From their own point of view, the Liberal Democrats are probably smart to stand apart and be free to criticise its outcome.

Modelling Butler on the inquiry by Lord Franks into the Falklands War does not suggest that the Prime Minister thinks he's taking any risk of this leading to resignations in high places, either within Government or the intelligence services. Of Franks's investigation into the blunders that preceded the Argentine invasion of the Falklands, James Callaghan observed: "For 338 paragraphs he painted a splendid picture, delineated the light and the shade, and the glowing colours in it, and when Franks got to paragraph 339 he got fed up with the canvas he was painting, and chucked a bucket of whitewash over it."

Everyone - even Tony Blair - must hope for better than that from Lord Butler and his colleagues. Not just to find out what went wrong in the past, but also for the sake of our security in the future, it is absolutely vital to establish why there were what Jack Straw so delicately calls " discrepancies" between the intelligence and the reality.

The threat of weapons of mass destruction being developed by rogue states or proliferating to terrorist groups is not simply the product of the paranoid imagination of the Prime Minister. He is correct when he asserts that this is one of the serious menaces of the early 21st century.

Because of the Iraq war, all the argument has revolved around the exaggeration of threats. Less remarked upon is how intelligence - perhaps because of the fixation with Saddam of their political masters - seems to have napped over other threats.

The investigation the other side of the Atlantic will be examining not just why Iraq's capability was so overstated, but also why intelligence seems to have underestimated programmes to develop weapons of mass destruction pursued by Libya and Iran.

Restoring credibility to intelligence will be as difficult as it is crucial. Because, at the moment, warnings to the public about threats from terrorists and rogue states could be absolutely correct. And a lot of people would simply not believe it.