The contentious issue of Iraq and its purported Weapons of Mass Destruction was resurrected last night after the UK Government was ordered to publish a draft of its controversial dossier on what turned out to be Saddam Hussein's non-existent arsenal.

The document by John Williams, Foreign Office press chief at the time, was an unpublished early version of the dossier, which was unveiled by ex-PM Tony Blair on September 24, 2002.

The Foreign Office appealed against the order last year by Richard Thomas, the Information Commissioner, that it should release the draft, claiming that to do so would not be in the public interest.

But yesterday the Information Tribunal rejected the FO appeal, saying: "We do not accept that we should, in effect, treat the Hutton Report as the final word on the subject." It is not yet clear whether the department will appeal to the High Court.

What people will be interested in is whether or not there are substantial differences between the Williams draft and the published version; there were claims that qualifications about Iraq's alleged WMD were redacted out of the final version.

There have been suggestions - denied by Mr Williams - that the draft contained the first mention of the claim that the late dictator could have launched a WMD strike within 45 minutes.

The tribunal ruled that the Williams draft "might be capable of adding to the public's understanding of the issues in question".

It noted how the public inquiry by Lord Hutton - which largely cleared the UK Government - was not handed the draft or addressed the questions which it might raise.

A Foreign Office spokesman said: "We will be studying the decision of the tribunal."