An official British investigation into two trailers found in northern Iraq has concluded they are not mobile germ warfare labs, as was claimed by Tony Blair and President George Bush, but were for the production of hydrogen to fill artillery balloons, as the Iraqis have continued to insist.

NO SMOKING GUN Members of a weapons inspection team examine a trailer in northern Iraq in late April. Photo by Dept. Of Defense/Reuters

The conclusion by biological weapons experts working for the British Government is an embarrassment for the Prime Minister, who has claimed that the discovery of the labs proved that Iraq retained weapons of mass destruction and justified the case for going to war against Saddam Hussein.

Instead, a British scientist and biological weapons expert, who has examined the trailers in Iraq, told The Observer last week: 'They are not mobile germ warfare laboratories. You could not use them for making biological weapons. They do not even look like them. They are exactly what the Iraqis said they were - facilities for the production of hydrogen gas to fill balloons.'

The conclusion of the investigation ordered by the British Government - and revealed by The Observer last week - is hugely embarrassing for Blair, who had used the discovery of the alleged mobile labs as part of his efforts to silence criticism over the failure of Britain and the US to find any weapons of mass destruction since the invasion of Iraq.

The row is expected to be re-ignited this week with Robin Cook and Clare Short, the two Cabinet Ministers who resigned over the war, both due to give evidence to a House of Commons inquiry into whether intelligence was manipulated in the run-up to the war. It will be the first time that both have been grilled by their peers on the Foreign Affairs Select Committee over what the Cabinet was told in the run-up to the war.

MPs will be keen to explore Cook's explanation when he resigned that, while he believed Iraq did have some WMD capability, he did not believe it was weaponized.

The Prime Minister and his director of strategy and communications, Alastair Campbell, are expected to decline invitations to appear. While MPs could attempt to force them, this is now thought unlikely to happen.

The Foreign Secretary, Jack Straw, is expected to give evidence the week after.

The revelation that the mobile labs were to produce hydrogen for artillery balloons will also cause discomfort for the British authorities because the Iraqi army's original system was sold to it by the British company, Marconi Command & Control.

© Guardian Newspapers Limited 2003

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