The curious thing is how few people have changed their minds on Iraq

What does it take to get people to decide they were wrong? What is remarkable about the invasion and the occupation of Iraq is how few people have changed their mind about the original decision to go to war. Not a single MP who voted with the Government on 18 March last year has said that he or she was wrong to do so. True, four Labour MPs have expressed their unhappiness. Eric Illsley, Jeff Ennis, Brian Donohoe and Ernie Ross, all of whom reluctantly supported Tony Blair in the important vote, now say the Americans have made a terrible mess of the after-sales service. But they stop short of saying that they should not have voted as they did.

Unlike Fritz Hollings, a Democrat from South Carolina and member of the US Senate. "I was misled," he said of his vote for military action. "I am embarrassed."

On both sides of the Atlantic, journalists have been just as reluctant to exercise the prerogative of adjusting their opinions in the light of new facts. Hence the interest in last week's leading article in The New York Times admitting that much of its reporting of Saddam Hussein's weapons programmes was "not as rigorous as it should have been". This unprecedented half apology, signed by "the editors", was a serious blow to the prestige of one of America's most august journalistic institutions. But it was not a recantation. The NYT was opposed to the war from the start, although in such balanced terms - or convoluted ones - that it might have been difficult to tell. It supported the disarming of Saddam, but opposed the "wrongheaded way this administration has gone about it".

In any case, the fact that Saddam's regime turned out to be hardly a threat to anyone outside Iraq should not change anyone's mind. What it should do, as David Kay, the former US weapons inspector, suggested, is require an apology from the intelligence services - and from newspapers such as The NYT which reported from similar sources - to political leaders.

Most people, for example, would not know Ahmed Chalabi from a hole in the ground, but assumed that they could rely on the British and American intelligence services to work out what was real and what were scare stories put about by Iraqi exiles desperate for the US to invade.

It remains Blair's strongest defence that he could not afford to risk that the intelligence was right - although it might help if he did not insist, as he did again last week, "I personally believe the intelligence we received was accurate. The conundrum of what has happened will be something that is resolved in due course."

The report of Lord Butler's inquiry into the accuracy of intelligence, to be published in two months' time, promises to be a fascinating document. But, unless it reveals that Blair lied, which is unthinkable, minds will continue to be resolutely unchanged - at least on grounds that the threat was bogus.

There was another aspect to the case for war, however, and it is that which has recently caused a small queue to form outside the anti-war confessional. The photographs of Iraqi prisoners being tortured and humiliated have battered the human rights case for liberating the Iraqi people from a monstrous dictator. Curiously, this has had more effect over here than in the US, although it was never part of the Government's legal case for war. It started with David Rose in the London Evening Standard on 10 May. He had written articles for the (pro-war) Observer about Saddam's weapons of mass destruction that turned out to be wrong, but it was the pictures from Abu Ghraib that caused him to "look back with shame and disbelief". Then there was Mary Ann Sieghart in The Times on 13 May: "I've had enough." And Tony Parsons in the Daily Mirror on 17 May: "We were hoaxed. By Blair."

What is surprising, though, is how few of them there have been. In America, the reaction to the setbacks of the war party has been even more muted. The great syndicated columnists have been unmoved. The Washington Post which, unlike its great New York-based rival, was in favour of the war, has merely turned down the volume.

Nor is it only the commentating and political classes who refuse to change their minds. In this country in June last year, the opinion pollsters ICM found that, by a margin of 48 per cent to 40 per cent, the British public said that the war to remove Saddam was justified. This month, ICM found that the gap had narrowed to 44 per cent against 43 per cent. That puts the media coverage of Iraq over the past year in perspective.

Just think what has happened over the past year, and how high-pitched the anti-war press, which includes the Daily Mail, has been. The BBC reported that "most people in intelligence weren't happy" with the case for war. The BBC's source was found dead in a wood. The inquiry into his death subjected the case for war to corrosive scrutiny. When the Prime Minister was exonerated by the inquiry, his vindication was so complete that it provoked a bitterly disbelieving backlash. While the situation in Iraq became progressively worse, war-related bad news kept coming: the bugging of Kofi Annan; the Madrid bombings; the 52 ex-diplomats complaining about our closeness to Bush. And then torture. For Blair, once the luckiest politician on the planet, the torture never seems to end.

And yet, what was the net effect of all that on the British public? A swing against the decision to go to war that is about the same as the margin of error. Do the British people pay no attention to the media? Or are they just extraordinarily fixed in their views? The answer is probably that most people made up their minds in the year or more before the war, and did so on grounds that have not been seriously challenged by subsequent events. At the most basic level, the argument was that Saddam was a dangerous man and that it was right to get rid of him. Neither the absence of weapons of mass destruction nor the abuse of Iraqi prisoners can change that. The only thing that could would be evidence that the Iraqi people wanted Saddam back, which they do not.

Contrary to the impression often given by an unlikely conspiracy between the Prime Minister and his most vocal opponents, the judgement of the decision to go to war was a balance. There were, at the time, good arguments against it, principally the dangers of inflaming extreme anti-American and anti-Western sentiment among Arabs and Muslims. But the arguments in favour were good too, namely curbing of biological and chemical weapons proliferation and freeing the Iraqi people. It seemed to me at the time that the balance was tilted in favour of the use of force, and nothing that has happened since has altered that. But perhaps the people who really need to change their minds are those who claim to be sure - it is their certainty, either way, that seems misplaced.