Make no mistake, the John Williams draft of the Iraq dossier, finally released yesterday, is a smoking gun. The document proves that Williams (a spin doctor friend of Alastair Campbell) who gave his own view of the affair in an article for Cif on Monday, was in the thick of drafting the document that took Britain to war. He wrote what became the dossier's executive summary. When the dossier was published, false claims from Williams were presented as "judgements" of the Joint Intelligence Committee (JIC). It does not get any more serious than that.

The first thing the Williams draft does is to show that the government lied to the Hutton and Butler inquiries and to parliament when it claimed that the Williams draft did not influence subsequent versions and was put aside when JIC chairman John Scarlett made a "fresh start" the next day.

Here's what the Williams draft said in its bullet-point summary:

"Our judgement is that iraq is covertly attempting to acquire technology and materials for use in nuclear weapons."

And here's what Scarlett's draft said:

"Our judgement is that iraq is covertly attempting to acquire technology and materials for use in nuclear weapons."

The earlier versions of this claim referred only to technology and materials "with nuclear applications". There was never any certainty that Iraq was developing nuclear weapons (it wasn't). Obviously, any similarity between the two exaggerated claims is explained by the fact that one was based on the other. It is astonishing that the government is still claiming that the Williams draft was immediately "set aside".

Some of Williams' sexing-up didn't survive the drafting process. But some did. Williams appears to have invented the claim that the Iraqis had developed mobile biological weapons facilities, where previous wordings only said that they had sought to do so. The claim that Saddam had weapons of mass destruction rather than just seeking them was key to the politicians' and spin doctors' claim that he was a current threat.