Tony Blair and George Bush were orchestrating a witch-hunt against Saddam Hussein that ended with the Iraq War, according to a former UN weapons inspector.
Hans Blix said the two leaders behaved like 17th century witchfinders in their willingness to oust the dictator.
In an interview with the Mail, he revealed that Mr Blair tried to force him to change his mind about the absence of WMDs in Iraq to placate the Americans.
The former Swedish diplomat, who headed the UN weapons inspection team in the run-up to war, concluded that Mr Blair and Mr Bush 'misled themselves and then they misled the public'.
He said: 'They were convinced they had their witch in front of them, and they searched for the evidence and believed it without critical examination.
'I'm not saying they acted in bad faith [but] they exercised very bad judgment. A modicum of critical thinking would have made them sceptical. When you start a war which cost thousands of lives you should be more certain than they were.'
Mr Blix dismissed the 'dodgy' Downing Street dossier on Saddam's weapons which made the case for war as 'a politician's twist'.
The claim that Iraq could fire chemical weapons in 45 minutes was 'hyperbole'. Mr Blix's inspectors viewed 700 supposed WMD sites in the months before the war but found nothing more than a handful of empty chemical munitions.
Five weeks before the invasion he revealed these findings to the UN and six days later Mr Blair told him his report had undermined American support for the UN process.
But Mr Blix stuck to his guns and warned the former prime minister not to invade, telling him: 'It would prove paradoxical and absurd if 250,000 troops were to invade Iraq and find very little.'
The 81-year-old said Mr Blair could have slowed the rush to war had he wanted to.
'If the UK had really insisted then on the UN path being exhausted, they could have slowed the military build-up ... but that wasn't the case,' he said. 'They eventually had so much military in the Gulf that they felt they had to invade.'
Bush and Blair
Mr Blix accused Mr Blair of 'legal tap-dancing' by claiming that existing UN resolutions gave the green light for war.
He added: 'The war, in my view, was illegal, yes. The British knew the evidence [of weapons] was thin, and they should have remembered that before they started shooting.'
Asked whether Mr Blair could be tried for war crimes, Mr Blix said: 'Well, yes, maybe so. Well, we'll see. It's not very likely to happen.'
Mr Blix said he would have been happy to testify to the Chilcot inquiry into the war but had not been asked to attend.
The inquiry heard yesterday that British troops were deliberately put in greater danger in order to increase Mr Blair's influence with the Americans.
Lieutenant General Sir Anthony Pigott, a former deputy chief of the defence staff, said Britain committed a 'meaty' land force in the hope that it would buy influence.
'You buy that on your contribution and your willingness to put - not just boots on the ground - people in danger,' he said. 'They know you are a serious player.'
The chances of Gordon Brown being called to give evidence increased yesterday when the inquiry heard he had refused to release additional funds to rebuild Basra following the invasion.
The claim was made by diplomat Dominic Asquith.
As a Swedish diplomat, Hans Blix is a man who chooses his words very carefully and very sparingly. But as he searches for the right way to describe the behaviour of Tony Blair and George Bush, as they prepared to wage war on Iraq, there is no mistaking the depth of feeling behind his analogy.
They were, he says, 'like witch-hunters of the 17th century' - men who were so desperately seeking to justify the invasion on the grounds that Saddam Hussein had stockpiled weapons of mass destruction, that they were deaf to reason and blind to logic.
'They were convinced they had their witch (Saddam) in front of them, and they searched for the evidence and believed it without critical examination'.
The result, says the former UN weapons inspector, was that Blair and Bush 'misled themselves, and then misled the public.
'I'm not saying they acted in bad faith (but) they exercised very bad judgment. A modicum of critical thinking would have made them sceptical. When you start a war, you should be more certain than they were.'
This is devastating analysis from a man who, perhaps more than any other, knows how deeply flawed the evidence that led Britain and America to war truly was.
When they began the search, in November, 2002, it was clear that he and his inspectors faced a daunting task.
They were despised by the Iraqis, who were affronted by their presence, and mistrusted by hawks in the Bush administration, who regarded them as hopelessly ineffectual (vice-president Cheney openly dismissed them as 'useless').
But in his unfussy, methodical way, Dr Blix - a Cambridge-educated international lawyer - was determined to investigate as thoroughly as possible whether Saddam really did possess germ warfare capabilities, as the British and Americans insisted.
As Dr Blix recalled, when we spoke this week in his Stockholm apartment, adorned with exotic artworks and colourful rugs, this sometimes necessitated almost farcical cat-and-mouse games.
'They misled the public... yes, it's conceivable both could end up on trial'
For at first the Iraqi escorts were determined to obstruct the inspectors at every turn. 'We would gather outside our base and say we were going in one direction, then after driving off we would abruptly change tack, so they never knew where we were heading.
'We also ensured that our daily targets, such as military installations or laboratories, were never transmitted directly from New York (where the inspectors were based), and we never used ciphers or telegrams. All the information was sent by courier.'
Despite these difficulties, by the following March they carried out some 700 inspections at 500 sites where, according to western intelligence and other supposedly reliable sources, WMD were suspected to have been stored.
And for all their efforts, they had found nothing more than a handful of empty chemical munitions.
This was not the conclusive proof that Dr Blix sought, of course, because, as he points out, it is almost impossible to prove that something does not exist.
Nonetheless, it suggested that Iraq may not have any WMD, much less the capability to strike the West at 45 minutes' notice, as the British Government had claimed months earlier in its infamous 'dodgy dossier'.
In an address which now seems laudably cautious and prescient, he aired his views to a packed meeting of the UN Security Council, precisely five weeks before the invasion, urging that his team be given more time to complete their search.
'I was not talking about days or weeks, nor about years, but a few more months,' he says.
Six days after he delivered his speech, however, he received a phone-call from Tony Blair.
The Americans had been deeply disappointed by his report, which had undermined their faith in the UN process, intoned the British Prime Minister.
Clearly hoping to convince Dr Blix he was being over-accommodating towards Saddam, Blair added that it wasn't only the British and U.S. intelligence services who felt sure that weapons really did lie hidden in Iraq. The French, Germans and even the Egyptians concurred.
Unlike others subjected to Blair's persuasive powers, however, Dr Blix stuck firmly to his position. 'It would prove paradoxical and absurd if 250,000 troops were to invade Iraq and find very little,' was the essence of his response.
Except for one chance encounter at a climate change meeting in Sweden last year, when they shook hands and exchanged a few pleasantries, that uncomfortable conversation almost seven years ago was the last they have had.
Given that Dr Blix possesses such a wealth of knowledge about the behindthescenes chicanery that precipitated the invasion, we might have expected their paths to cross again during Sir John Chilcot's inquiry, which began last week.
Blair is due to give evidence early next year. But, thus far at least, the weapons inspector has not been called even though, at 81, he still travels widely on speaking engagements, recalls the events of 2002/3 with formidable precision, and would certainly make a compelling witness.
Instead, he is following every twist of the inquiry online (when I arrive he has just finished reading more than 100 pages of testimony provided by Blair's former foreign policy advisor Sir David Manning).
So what would he tell Chilcot, were he to appear? The question prompts a three-hour discourse broken only when an apologetic Dr Blix suddenly heads for the kitchen, apologising that he has forgotten to offer me tea.
For one thing, he says, it should have been perfectly plain to Blair months before the war that the 'intelligence' on which he placed such great store was risibly inaccurate.
There were many reasons to suspect this, not least the disclosure that a contract which purportedly proved that Niger had sold Iraq 'yellow cake' - concentrated uranium powder used to make nuclear weapons - was a forgery.
Dr Blix also takes issue with a statement made at the Chilcot inquiry this week by Sir David Manning. He told the hearing that Dr Blix's team had examined ten of 19 sites named by British intelligence and 'turned up some quite interesting stuff'.
But the weapons inspector says he ought to have been asked what 'interesting' really meant.
'Yes, they led to interesting results, that's true - but never to WMD. We found a few documents and some conventional weapons - grenades and so forth - nothing more.
'The message that should have gone to the intelligence services was that your sources must have been bad. If your sources are bad in these cases, maybe they're bad in others.'
Then there was the dodgy dossier. In 2004, finally forced to withdraw its utterly fallacious 45-minute claim, Jack Straw informed Parliament that the dossier had been shown to Blix in September, 2002, and he 'shared' the intelligence service's fears.
However, it later emerged that Dr Blix had only seen the dossier before it was ' sexedup' on Alastair Campbell's instructions. And this was, of course, long before his team had set foot in Iraq.
In any case, Dr Blix now disputes that he ever gave the dossier his blessing. 'I read it only casually because it was something that would have been fed to our inspectors to see what they thought, and we had no comment at all about that,' he recalls.
As the crisis escalated, Dr Blix says, it was as though Bush had set in motion a 'train' which was hurtling pell-mell towards conflict. Blair was very much a passenger on this train, but at least he wanted to keep the UN on board.
Switching metaphors, he says it was as if two clocks were ticking at very different speeds - and while his inspectors were working methodically to one in an effort to avert bloodshed, Bush was racing towards conflict by another.
One of Dr Blix's major criticisms of Blair is that he failed - or did not even try - to slow Bush down, so that the Americans and British and the UN at least marched in synchronicity.
For had he been given just three more months in Iraq, he is convinced, he could have ended any realistic doubts about the existence of WMD - and then not even Bush and his neocons could have sustained a case for war.
Instead, as the massive military build-up continued, he and his team were given just two days notice to leave Baghdad before Operation Iraqi Freedom began, and by June, after tidying up loose ends, he had left his position.
However, he says he knew for certain soon after the occupation that Saddam had no chemical or biological weapons. For by then Iraq's military scientists and administrators were free to speak, and knew they would have been rewarded for leading the coalition forces to WMD sites. But they couldn't do that - because they didn't exist.
Disgracefully, however, it took the British and Americans months to admit that they weren't there, and it wasn't until January, 2005, that the U.S. announced that the search had finally been abandoned.
WMDs? We found none. Just papers, and grenades'
How did he feel when the troops poured in, I asked him. 'Sad, sad, sad,' he replies. 'A failure. The majority of UN members wanted more inspections, and they declined to authorise a war that shouldn't have taken place.'
His only consolation was the knowledge that he and his team had tried, and kept trying to the eleventh hour to provide the evidence needed for a peaceable outcome.
'What would the world have thought if the UN had given the green light for war? The inspection would have been discredited; the UN would have been discredited. So in that sense it was a victory for critical thinking and professionally searching for facts.'
He is in no doubt that war was prosecuted unlawfully, then?
'The war, in my view, was illegal, yes. Assume that Saddam had obstructed the inspections: then it's conceivable that the Security Council would have authorised it. They might have said, yes, he's threatening the peace.
'The British knew the evidence [for the existence of weapons] was thin, and they should have remembered that before they started shooting.
'If you think your wife is being unfaithful, and you shoot her, but then find out you were wrong, it is no use claiming that you thought you were right at the time. You are still guilty.'
Were Blair and Bush guilty of war crimes, as their fiercest critics maintain? 'Well, some people...' he begins, then stops himself, adding after a lengthy pause: 'That would have to be tested by tribunal before you established it. I'll leave that for others to decide. I'm not conducting any campaign.
'But you have to be aware that the U.S. and UK acted on authorisation from Congress and Parliament.'
And what if Congress and Parliament had been deliberately misled? 'Well, I have never said they acted in bad faith; that they knew there were no WMDs. As I say, the expression I would use is that they misled themselves, and then misled the public.'
Later, when I invite him to put on his lawyer's gown and ponder whether a criminal case might be possible, he asks: 'Well, who would sue them? Before what tribunal?
'Bush, at least, could not be tried before the International Criminal Court in the Hague because the U.S. is not a signatory to it. But I wouldn't say it's impossible. A national tribunal maybe.'
So Blair could conceivably stand trial at, say, the Old Bailey? 'Well, yes, maybe so. Well, we'll see. It's not very likely to happen.'
Moving back to more comfortable ground, he says that Blair has been tried by the court of public opinion. After the war he fared badly in local elections, and ultimately he relinquished the premiership. Dr Blix is also convinced that it was lingering anger over his rush to war alongside Bush that cost him the presidency of the European Union.
'You had France and Germany who were against the war. They wouldn't take lightly to it, but I'm sure there were also other reasons.
'I don't think they wanted such a flamboyant figure, and I think that's right. They were really looking for a chairman rather than a president - to keep things on an even keel.
'But there would be fairly deep feelings [about the war]. I think there's an attempt to say that this is behind us; we need a patched-up Europe. But still, here was a guy who was very firmly on the other side, and on the U.S. side.'
With the conversation drawing to a close, he leads me into his and shows me his favourite cartoon, mounted on the wall.
It depicts a frustrated George Bush holding a bomb fuse in one hand and vainly trying to strike a match on Dr Blix's bald head with the other.
'Look - he seems so frustrated, and I'm just sitting there, all stubborn,' he chuckles, 'I think that perfectly sums it up.'
His life has now moved on, he tells me, and these days he spends almost as much time lobbying for nuclear energy - his favoured solution to climate change - as he devotes to the abolition of nuclear weapons.
However, the Chilcot inquiry has clearly reawakened so many memories, and he is not one to stand by and watch history being distorted.
Sir John would only need to lift the phone and - much to Blair's discomfort - the man who warned him about the absurdity of going to war on a false premise would board the next London-bound plane.