Focus: Part Two The Evidence - How could Iraq attack in 45 minutes with weapons it had taken apart?

So did Saddam Hussein have weapons of mass destruction ready to use, as the Prime Minister claimed? Two weeks of hearings by the Foreign Affairs Committee have highlighted the reservations of Cabinet ministers before the conflict, but provided no clear answers about the evidence they were given. Here Dr Glen Rangwala raises the main unanswered questions.

What is the origin of the claim - made four times in the September dossier - that Iraq could use chemical and biological weapons within 45 minutes?

One of the major issues that led the Foreign Affairs Committee to launch an inquiry has been left even more confused at the end of the hearings. Alastair Campbell, Downing Street's director of communications, said on Wednesday that the assertion that Iraq could use prohibited weapons within 45 minutes existed in "the very first draft" of the dossier. Mr Campbell said he had "many, many discussions" with the chairman of the Joint Intelligence Committee on this very point.

This account was contradicted two days later by the Foreign Secretary, Jack Straw, who told the Committee that the claim was not in the first draft of the dossier because the information had not come to light until early September, only a couple of weeks before the document was released. Mr Straw was then passed a note, and said Mr Campbell would clear up any confusion in his written evidence to come.

Adam Ingram, a junior Defence minister, has said that the source of the claim was a single individual who was then serving as a high-level official within the Iraqi regime.

To confuse matters further, Tony Blair told journalists in April that intelligence sources had told him Iraq had started a policy of concealing its weapons six months before inspectors had even entered the country - that is, by May 2002.

According to Mr Blair, he had "no doubt" that this meant that "it was going to be far more difficult for them [Iraqis] to reconstitute that material to use in a situation of conflict." If it was known that Iraq had dismantled its weapons in May 2002, then how could intelligence from September 2002 indicate that Iraq could use these weapons within 45 minutes?

The Government needs to account for the source of the 45 minutes claim, either by naming the individual who provided the information or by indicating his or her status. Why was this source seen as credible by the intelligence agencies? Most importantly, did the Government accept the validity of this information after September? Mr Straw has attempted to play down the significance of the claim by asserting that it was not repeated by ministers before the conflict. By contrast, this may indicate that ministers were aware from late 2002 that the allegation was not credible. If this were so, it would reveal that the Government was being duplicitous in putting out information and failing to retract it when it was taken as no longer valid.

Did intelligence assessments before the invasion portray Iraq as a serious threat?

In September 2002 Mr Straw described Iraq as "uniquely dangerous" and a serious threat to the UK. He justified this claim to the Foreign Affairs Committee by asserting that Iraq's "illegal al-Samoud missiles" had "a range of 650 kilometres", which could "attack our direct assets in Cyprus". The September dossier stated that Iraq had missiles with this range.

However, Mr Straw made a simple factual error in his presentation to the Committee on this issue last week. The UN inspectors found that al-Samoud missiles, when fired without a guidance system, had a maximum range of 183km, not 650km.

This was beyond the UN-imposed limit of 150km, and the inspectors began to destroy the missiles with Iraqi compliance. Inspectors found no evidence of missiles with a range of 650km. As a result, Mr Straw's sole basis for a claim that Iraq was a threat to the UK national interest falls away. Was this acknowledged in intelligence assessments prior to the invasion?

Did intelligence agencies really believe that Iraq could have preserved chemical and biological weapons that it produced before 1991?

Mr Straw has admitted that he asked for details on one theme to be added to the September dossier: that some of Iraq's weapons produced before 1991 had not been accounted for by UN inspectors. In the run-up to the invasion, these were the only weapons that the British government made reference to in their allegations about Iraq. By contrast, few experts believe that chemical or biological weapons - with the one exception of mustard gas - could have been preserved successfully by Iraq for more than 12 years. In addition, the most prominent defector from Iraq, Saddam Hussein's son-in-law Hussein Kamal al-Majid, claimed that the regime decided in 1991 not to retain any prohibited weapons. The British government was aware of this claim from 1995 onwards, although it only became publicly known through a leak this year. Was there any information to suggest that Iraq had either managed to retain weapons produced before 1991, or had even attempted to hold on to these weapons?

Did MI6 believe Iraq was unlikely to use chemical and biological weapons in the event of an invasion?

Mr Straw told the Committee that "the assumption was that he [Saddam Hussein] would use" chemical and biological weapons during the conflict. This was contradicted by Clare Short, who resigned from the Cabinet after the war. She revealed to the Committee that MI6 had prepared a paper which said that, in her words, "there is a risk, and it was thought to be not very high", that chemical and biological agents would be used.

Was such a paper produced? What reasons were given for the low risk assessment? And why wasn't this information conveyed to the public, if only to allay the fears of families of British service personnel?

The expert witness

The Government's "dodgy dossier" on Iraq might never have acquired that description had it not been for Glen Rangwala, a 28-year-old Cambridge lecturer in political theory and Middle East studies. Dr Rangwala immediately saw that much of the dossier had been plagiarised from Jane's Intelligence Review and an article by an Oxford PhD student, Ibrahim al-Marashi. With the help of an internet security expert, he also discovered that the last four people to have processed the document all worked for Alastair Campbell, Downing Street's director of communications. That was one of the main reasons for Mr Campbell's appearance before a parliamentary committee last week. The lecturer has been following the issue of Iraq's "non-conventional weapons" since the mid-1990s, having seen the effects of Iraqi chemical weapons in western Iran. InThe Independent on Sunday and in written evidence to the committee, Dr Rangwala's expertise has dismantled British and American claims about Iraq's WMD.

Raymond Whitaker