By Barnaby Mason BBC diplomatic correspondent

The phrase "last chance" has been over-used in the Iraq confrontation, but it may turn out to be justified to describe what happens over the next crucial week.

The UN weapons inspectors are looking for much more active co-operation from the Iraqi Government in accounting for and eliminating any weapons of mass destruction.

US President George W Bush has dismissed in advance what he calls another round of empty concessions from President Saddam Hussein, a last-minute game of deception.

But France and Russia are among those who insist that the inspectors must continue their work and that war is not - at present - justified.

Unanswered questions

In advance of this weekend's visit to Baghdad by the chief UN inspectors, Hans Blix and Mohammed ElBaradei, Iraq showed signs of bending under the pressure.

France says inspections should continue

It allowed an Iraqi biologist to be interviewed for three-and-a-half hours without a government minder sitting at his shoulder.

The first question is whether the interview heralds many more interviews - this time of scientists the inspectors have asked to talk to.

That would be more significant, though there would still be questions about how much they might continue to feel subject to official intimidation.

Then there is the question of the Iraqis agreeing after weeks of opposition to the use of US surveillance aircraft.

	:	Powell's report
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Or the demand that they should pass legislation formally prohibiting anyone from working on weapons of mass destruction - it is hard to see what practical difference that would make in a dictatorship.

Attitude shift

British officials argue that concessions on individual points are nowhere near enough.

CURRENT SECURITY COUNCIL

For military action: US*, UK*, Spain and Bulgaria Sceptics or opposed: France*, Russia*, China*, Germany and Syria In doubt: Angola, Cameroon, Chile, Guinea, Mexico and Pakistan Nine votes and no veto required to pass a resolution *veto-wielding countries

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What is needed is a dramatic shift in Iraq's attitude, a wholehearted willingness to disarm.

One way the Iraqis could demonstrate that would be to start accounting for the large quantities of chemical weapons and other banned materials which the inspectors are sure they had in the past.

As Mr Blix put it, they have either to do that or produce what they have for destruction.

It has become clear over the past few days that the governments opposing military action are no longer seriously arguing that Saddam Hussein does not have any weapons of mass destruction.

The argument now is whether what he has constitutes a grave and imminent threat, and what to do about it.

The outcome of the inspectors' visit to Baghdad and their report to the Security Council next Friday will largely determine the attitude of big powers like France, Russia and China.

New resolution

And if the inspectors say that Iraq is not fully co-operating, the US and Britain will start working seriously to gather support for a new resolution.

The French and the Russians say the time is not right for such a resolution, but they have not said they will veto it.

	:	Iraq facts
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Even if they and China were to abstain, it might still pass.

There are various possibilities for the shape of a new resolution. Washington and London would prefer one that explicitly authorised war.

But an alternative would be a declaration that Iraq had violated - was in material breach of - last November's resolution 1441, and recalled the serious consequences the Security Council threatened then.

'Diplomatic end-game'

Many countries would be prepared to support an American-led war provided that it was approved by the UN.

Arab allies of Washington need a new resolution in order to blunt public hostility at home.

And European governments struggling to convince their own people - not least in Britain - would feel on much safer ground.

The other factor tending to push politicians into line is the feeling that the war is all but inevitable anyway and, if so, they had better not risk damaging their long-term relationship with the US.

Germany is in the most awkward position, having more or less staked out a position that it will not support military action in any circumstances.

Senior American officials are openly questioning whether it can any longer be considered a reliable ally.

This is not to say that war backed by the UN is a foregone conclusion. The events of the next week may not finally settle the matter.

But all the players in the crisis are entering the diplomatic end-game.