Bit by bit, how case for war has unravelled, leaving Blair dangerously exposed

Tony Blair's stated reason for Britain going to war against Iraq - the threat from its weapons of mass destruction - was deemed by Lord Hutton to be outside his remit.

Yet the judge's inquiry unearthed a wealth of evidence on the subject, with e-mails and previously classified documents revealing the intelligence behind the infamous dossier.

Moreover, virtually every expert in the field has now concluded that Saddam did not have any major stockpiles of weapons and had not developed his programmes significantly since the 1990-91 Gulf war.

Here, The Independent examines just how the claims about WMD have been pulled apart since Britain and the US first raised the spectre of an imminent threat of attack.

1. THE NUCLEAR THREAT

As with most of the WMD claims, the two main sources of the allegations came in the Downing Street dossier published in September 2002 and in Colin Powell's "seminar" to the UN Security Council in February 2003.The main charges were that Iraq was importing tubes to use as centrifuges for a nuclear weapon and seeking to import uranium from Niger.

WHAT HUTTON DISCOVERED

The original draft of the UK dossier was cautious about the nuclear issue. The Defence Intelligence Staff (DIS) warned "Iraq could not produce sufficient weapons grade material for a single weapon for at least four or five years and only once sanctions have been removed".

But Alastair Campbell said he and Mr Blair both preferred an earlier intelligence assessment suggesting a dirty radiological device could be produced within one to two years. The dossier was accordingly made stronger.

WHAT THE EXPERTS SAY

Mohamed ElBaradei, the head of the International Atomic Energy Agency (IAEA), dismissed the aluminium tubes claim. The IAEA also found the documents on which the Niger claim was made turned out to be fakes.

2. THE CHEMICAL THREAT

General Powell told the UN that "Iraq today has a stockpile of between 100 and 500 tons of chemical weapons agent".

The dossier claimed Iraq had taken over civilian plants since the mid-1990s to produce weapons agents. Specific sites were of concern, such as the al-Dawrah foot-and-mouth vaccine institute and the Amariyah sera and vaccine institute.

It claimed the phosgene plant at al-Qaqaa was "of particular concern". But when the plant opened to journalists it was proved to be a false claim.

WHAT HUTTON DISCOVERED

Evidence from a "Mr A", a chemical weapons expert, revealed he agreed with Iraqi comments that the reference to the phosgene plant was "a pretty stupid mistake for the British to make". Brian Jones, formerly of the Defence Intelligence Staff, complained another of his chemical weapons experts objected to claims chemical weapons were still being produced. A late piece of evidence to the inquiry showed the DIS warned on 12 September that "we have absolutely no idea how many chemical weapons or the quantity of agent".

WHAT THE EXPERTS SAY

Hans Blix, the former chief UN weapons inspector, said at his last appearance before the Security Council in July that the inspectors had "not ... found evidence of the continuation or resumption of programmes" of WMD. David Kay, outgoing chief of the Iraq Survey Group, said on Wednesday: "We were almost all wrong - and I include myself here. We have not discovered any evidence of stockpiles."

3. THE BIOLOGICAL THREAT

General Powell made this a main part of his UN address - the claim that mobile laboratories were in Iraq making biological agents for weapons.

WHAT HUTTON DISCOVERED

When asked by No 10 to provide estimates of the amounts of biological agent produced, the DIS replied "this is an almost impossible question". It showed the DIS was sceptical about the existence of mobile labs.

WHAT THE EXPERTS SAY

Mr Blix said that only "food-testing mobile units and mobile workshops" and containers with "seed-processing equipment" had been found.

4. IMMINENT THREAT/TERRORISM

The dossier claimed Saddam could deploy chemical and biological weapons within 45 minutes. The dossier's title was changed from referring to "WMD programmes" to "weapons". Mr Blair insisted WMD were a "current and serious threat". President Bush claimed links between Saddam and al-Qa'ida. Downing Street called it a "potential link".

WHAT HUTTON DISCOVERED

The 45-minute claim was single- sourced and objected to by the DIS. John Scarlett admitted the original intelligence was referring to battlefield weapons not long-range missiles. Sir Richard Dearlove, the MI6 chief, agreed the claim was given "undue prominence".

WHAT THE EXPERTS SAY

David Kelly said the 45-minute claim was "risible". Brian Jones and other experts felt it was too strongly worded. Mr Blix, said the claim was "pretty off the mark".There has never been any evidence of a link between Saddam and al-Qa'ida.

'TONY BLAIR HAS BEEN LET OFF THE HOOK'

Ben Ferguson, A-level politics student, 16, Manchester

"I'm astonished by... the way the Prime Minister and civil servants emerged unscathed... My suspicions about Alastair Campbell were compounded by watching him on Newsnight last night... he was aggressive and defensive."

Soha Sheikh, 19, media communications student at City University

"The outcome of this inquiry seems like a distraction from the fact that we did not have a solid argument for the urgency of war. A large portion of this country did not want war to happen yet it went ahead."

Tony Benn, 78, anti-war campaigner and former MP, Westminster

"The Hutton terms of reference were deliberately set so tightly that it was simply to decide whether Gilligan or Campbell was right. Last year the real question was whether the war was right."

Kiran Chowdhary, customer service adviser, 28, Edinburgh

"It was a complete whitewash. I am surprised the Government got away with it so completely. It just makes people think it's a bit of a cover-up. The war was wrong, most people know that, but the Government won't admit it."

Sheila Drummond, 56, garden designer, Edinburgh.

"Blaming the BBC is a great way of diverting attention from the real issue of why we went to war if nobody can find any evidence of weapons of mass destruction. The Hutton inquiry was a smokescreen."

Mariella Frostrup, broadcaster, 41, central London

"Tony Blair has been let off the hook in terms of the question 'did he sex up the document'. But that was a distraction from the real issues. There are still so many unanswered questions, for example where are the weapons?"