THE BBC last night disclosed a previously unscreened interview with the late weapons expert Dr David Kelly in which he said Saddam Hussein could deploy weapons of mass destruction (WMD) within "days or weeks".

Dr Kelly said he was convinced Saddam was a real threat. But his comments about the timing of any WMD launch were seized on by Tony Blair's opponents.

They said it was further evidence that the Government's claim - made a month before Dr Kelly gave his interview - that Iraqi WMD could be deployed within 45 minutes was wrong.

The Tories renewed their call for a judicial inquiry into events leading up to the war and the Liberal Democrats said Dr Kelly's comments underlined the expert's scepticism about the No 10 claims made in a dossier published in September 2002.

Dr Kelly gave his interview to the Panorama programme in October the same year, but it was not broadcast.

Last night, one short extract was aired in a Panorama special on the events surrounding Dr Kelly's death - a week before the Hutton Report into events leading up to it is published. Further extracts were published on a BBC website.

Panorama editor Mike Robinson said the interview had been submitted to Lord Hutton's inquiry.

Dr Kelly was asked if Saddam was a real threat who possessed WMD and replied: "Yes. Even if they're not actually filled and deployed today, the capability exists to get them filled and deployed within a matter of days and weeks."

Dr Kelly killed himself last July after being named as the source for BBC reporter Andrew Gilligan's claims that the Government had "sexed up" its dossier on Iraq's WMD.

In the rest of his interview, not featured in last night's programme, Dr Kelly says Saddam's WMD posed a genuine threat to neighbouring countries.

"We are talking about Iran and Israel and certainly he can use those weapons against them and you don't need a vast stockpile to have a tremendous military effect."

But he said Iraq posed a lesser threat than before the first Gulf war: "Iraq's intrinsic capability has been reduced since 1990-1991."

Last night's programme repeats criticisms of Mr Gilligan over his Today programme broadcast which were aired in evidence to Lord Hutton's inquiry.

The reporter himself told Lord Hutton he was wrong to imply the Government had deliberately inserted a claim into its dossier about WMD being ready in 45 minutes knowing it to be false.

Panorama says BBC executives who stood by the reporter "bet the farm on a shaky foundation". They failed to investigate the basis for his report properly and knew he had been criticised in the past for "loose language".

The programme concludes that "No 10 did not override the assessment of the Joint Intelligence Committee" when it produced the dossier.

Shadow Foreign Secretary Michael Ancram said: "Dr Kelly's comments do place his views at odds with those presented in the Government's September dossier. They show his concern with the 45-minute claim.

"This interview reinforces the case for the full independent judicial inquiry into the run-up to the Iraq war which we have been calling for."

Downing Street refused to comment on last night's broadcast, in line with its policy of staying silent until Lord Hutton has reported.