In the course of his 90-minute multimedia presentation, Powell used three recordings of conversations between Iraqi military officials, eight satellite images of weapons facilities, a video of a fighter jet modified to spray chemical or biological agents and an empty vial.

There were three points to prove: Iraq's ability and attempts to produce illegal weapons; the futility of weapons inspections in the face of Iraqi dissimulation; and the existence of a working relationship between Baghdad and Al-Qaeda. Assuming the evidence he presented is genuine, Powell made a strong case on the weapons and Iraqi trickery, but failed to convince on what he called 'the sinister nexus between Iraq and the Al-Qaeda network.'

On the face of it, that should be enough. Resolution 1441 is concerned only with Iraqi disarmament. Terrorism does not come into the equation. If the US can prove that inspections cannot disarm Iraq, it will have made its case. 'Paragraph four of UN resolution 1441 . clearly states that false statements and omissions in the declaration and a failure by Iraq at any time to comply with and co-operate fully in the implementation of this resolution shall constitute . a further material breach of its obligation,' said Powell. 'It was designed to be an early test. They failed that test. By this standard, the standard of this operative paragraph, I believe that Iraq is now in further material breach of its obligations.'

Powell's case against Iraqi dissimulation rests on three points. Evidence that the regime ordered weapons to be concealed, evidence that it closely monitored the inspectors to pre-empt their investigations and evidence that it prevented key witnesses from giving testimony.

Two recorded conversations between Iraqi Republican Guard officers touched on weapons concealment, referring in one case to a modified vehicle that must be evacuated and in the other to cleaning out scrap areas because inspectors were coming to search for 'forbidden ammo'. Satellite images showed sites being cleaned out before they were searched. Powell claimed such activity - which he said was not normal at monitored facilities - was noted at nearly 30 sites in the run-up to visits by the UN team.

Perhaps the most disturbing evidence, but also the hardest to verify, was the US' assertion that Saddam Hussein had set up a 'higher committee for monitoring the inspection teams'. This committee allegedly reports directly to the president, is headed by vice-president Taha Yassin Ramadan and includes the Iraqi leader's son Qusay, as well as Emir al-Saadi, the primary point of contact between Baghdad and the inspections team.

'From our sources, we know that inspectors are under constant surveillance by an army of Iraqi intelligence operatives,' said Powell. 'Iraq is relentlessly attempting to tap all of their communications, both voice and electronics.'

The proof that witnesses were prevented from being properly interviewed is mainly in the public domain and was a point pressed home by chief weapons inspector Hans Blix. Powell backed it up with public statements by top Iraqi officials and reports of explicit threats by the Iraqi leadership to anybody who spoke to the UN.

The evidence of Iraq's weapons capability was similarly corroborative. Powell took the basic Blix report and added to it. Blix said Iraq must show it had destroyed the chemical, biological and nuclear capabilities it had admitted to developing in the 1980s and 1990s. He backed this up with defector reports of mobile biological agent facilities, factories hidden in trucks and train carriages that can be moved in secret across the country.

'The mobile production facilities are very few, perhaps 18 trucks that we know of,' said Powell. 'Just imagine trying to find 18 trucks among the thousands and thousands of trucks that travel the roads of Iraq every single day.'

As Powell told it, the case that Iraq has these weapons, is continuing to develop these weapons and is cheating the inspections process seemed pretty strong. Not so his assertions relating to terrorism. For the UN, the terrorism angle is largely irrelevant in any case. But in setting out the connection between Iraq, weapons of mass destruction and terrorist cells in Europe and Russia, Powell was making an obvious play to the US public and the sceptics in Paris, Moscow and Berlin.

The centrepiece of his case is an alleged Al-Qaeda 'associate and collaborator' called Abu Musaab al-Zarqawi. Powell said Al-Zarqawi had established poison camps in Taleban-controlled Afghanistan and in northern Iraq, outside the area of Baghdad's control.

The link to Baghdad, he said, came through Al-Zarqawi's two-month stay there in May 2002 and his connection between his own associates and Islamic extremists inside Iraq. He was also accused of involvement with the assassination of a US diplomat in Jordan last year. The evidence was sparse.

Moreover, his further allegations of an 'understanding' reached between Al-Qaeda and Iraq in the mid-1990s suggest nothing more than non-aggression between the two, something that could also be said for a number of other Middle East states.

Such evidence is also flatly contradicted by a UK intelligence report leaked to the BBC early on 5 February. The report said there had been some fledgling relations between Al-Qaeda and Iraq in the mid-1990s, but these had been low-level and soon broken.

In all, Powell's nexus of terrorism remains unspecified and tenuous. But his allegations of Iraqi weapons production look solid. Most importantly, Powell produced sufficient evidence to show that the inspections were futile. It is difficult to see how other Security Council members can actively vote against a resolution calling for action, although it is reasonable to presume that many will abstain. As far as the US is concerned, this presentation makes it impossible to back down. The Powell statement should be regarded as virtually a declaration of war.