By Mark Davies BBC News Online political reporter

The beads of sweat glistening on Tony Blair's face might have suggested a man facing more flak than he could handle.

As the latest prime ministerial press conference continued at Sedgefield Community College, so the perspiration gradually increased.

Mr Blair came across as someone who had made up his mind that military action is a real possibility

But if you're thinking Mr Blair was having a hard time, think again.

He may have subtly moved the argument about whether to take action against Iraq into a new phase - appearing to take a firmer line in the support of the prospect of war - but he was rarely flustered.

The prime minister has always been an accomplished performer under the glare of television lights, appearing to relish the challenge.

And his introduction of a monthly press conference - this time held in his constituency - has done nothing to dent that reputation.

Dossier

Although imperious at times, he clearly had it in mind to come across as open, frank and downright reasonable in the face of the inevitable questions about Iraq.

Blair vowed to set out the case against Saddam

He quickly tossed the press a story with the announcement that a long-awaited dossier on Iraq will come "in a few weeks".

As no-one knew when it was actually due anyway, it wasn't much of an offering, but at least it was something for the pack to feed on.

But what was more significant was an apparent hardening of his line on possible action against Saddam Hussein.

Whether he intended it or not, Mr Blair came across as someone who had made up his mind that military action is a real possibility.

Wary

As ever on such occasions, the audience most important to the prime minister lay beyond those sitting in front of him.

That conviction appears to suggest that we have entered a new phase in the argument

And he knows that he has a big job on his hands if he is to convince a wary public about the need for action.

So he pulled no punches in outlining what he said were Saddam's crimes.

And he stressed his view of the threat posed by the Iraqi leader and the importance of international backing for any action.

He's said that before, but he did also appear to move closer to supporting US hopes for "regime change" in Iraq.

Outspoken

He also steered carefully around the issue of weapons inspectors amid apparent US disdain for the role they can play in Iraq.

There was more strong backing for George Bush, and an outspoken attack on "straight-forward anti-Americanism".

To the domestic audience, Mr Blair aimed his message at one of what he said are two groups of doubters over attacks on Iraq.

One set, he suggested, are never going to change their minds - they are opposed to action against Iraq and always will be.

But he insisted that there are others who while doubtful now, may be persuaded when they see more evidence backing action.

Disquiet

By implication, that group of people are a long way from the Westminster village - and they are the people who Mr Blair hopes will eventually be persuaded by his words in Sedgefield and in the coming weeks.

Opinion polls, of course, suggest deep disquiet about the idea of attacking Iraq.

Many of his own MPs are worried, and party activists have a ready-made opportunity to voice their own concerns at Labour's conference in a few weeks.

The prime minister, however, seems to believe that such is the threat from Saddam that he can convince the bulk of the doubters that British troops may have to be called into action.

And that conviction appears to suggest that we have entered a new phase in the argument - the campaign to win public backing.