By Nick Assinder BBC News Online political correspondent

Tony Blair could not have stated it more clearly.

He is in no doubt that Saddam Hussein has weapons of mass destruction.

And that almost certainly means war - whether the weapons inspectors find a "smoking gun" or not, and whether the UN passes a second resolution or not.

Troop build-up

All the recent talk about the prime minister cooling on the idea of war was cast aside as he gave his most direct indication so far that military action against Saddam Hussein is inevitable.

His comments, in some of the most intensive questioning yet at one of these monthly press conferences, will have heightened the dismay amongst some cabinet ministers and many backbenchers deeply opposed to war.

They raise the question of exactly what the point of the UN weapons inspectors is.

They confirm suspicions he is ready to back President Bush in unilateral action against Saddam, even in the face of UN and domestic opposition.

Complete control

And they will almost certainly ensure the split on his own benches and inside the cabinet will deepen.

For the first time since these televised sessions started last summer, the prime minister faced a barrage of questions predominantly on one subject.

Previously he has been able to bat away "unhelpful" questions and move onto the next - but not this time.

That should not, however, suggest he gave anything away or looked anything other than completely in control.

Anything he said was exactly what he intended to say. And any hints he dropped were purely intentional.

At the end of it there was no clearer idea of when the war with Iraq would start - although the build-up of military in the region suggests sooner rather than later.

Stand down

But Mr Blair had answered two of the key questions that his army of critics have been posing - whether he is prepared to back President Bush in a war against Saddam without UN backing or if the inspectors continue to find no weapons of mass destruction.

Of course, if evidence is found, then it is quite possible the UN will be persuaded to back military action. And the prime minister is confident evidence will be found.

It also just possible that Saddam can be persuaded to stand down by some of his Arab friends.

Short leads critics

But failing these outcomes it now seems his critics' worst fears are about to be realised. And that may land him with a major leadership crisis.

If he goes to war under these circumstances he will not only face a public backlash in Britain, he will be isolated in the global community and probably spark a major cabinet split.

Gung ho

It would almost impossible for Clare Short to remain in the cabinet if he took that route and, if she resigned, others might feel obliged to follow suit.

Many ordinary Labour Party members may also quit the party and it is almost certain the government's popularity would slump.

It is not an exaggeration to suggest that such a course of action could even see a challenge to the prime minister's leadership.

Foreign Secretary Jack Straw has been careful not to be seen backing the prime minister's hard line.

And Chancellor Gordon Brown has done one of his traditional disappearing tricks.

Last week, much store was placed on the prime minister's insistence that the weapons inspectors must be given time to do their job.

Body language

That was seen as a softening of the line. In fact it has been the constant message from Downing Street ever since the UN agreed the strategy.

But it suited the prime minister's purposes to stress it at this particular time to suggest he is not as gung ho as many fear.

But from day one - that is from 12 September 2001 - the prime minister's body language has been pretty clear on this.

He genuinely believes Saddam is a real threat and that he is doing the right thing by preparing to finish him off.

If anything, his position appears to have hardened.