Reacting to the report by chief weapons inspector Hans Blix, the UK foreign secretary said Saddam Hussein could only secure peace by a "dramatic and immediate change" in his co-operation.

At this stage, there is no just or moral case for war Charles Kennedy

The UN must "hold its nerve in the face of this tyrant" and be prepared to back up its diplomacy with force should it become necessary.

Mr Straw was speaking in New York shortly after French foreign minister Dominique de Villepin called for the inspectors to be given more time.

"The option of inspections has not been taken to the end," the French minister said.

Liberal Democrat leader Charles Kennedy said the British government had to continue to support weapons inspectors and war at this stage was "inconceivable".

Failure

"It is clear they still have more work to do," he said.

"At this stage, there is no just or moral case for war."

But Tory leader Iain Duncan Smith said the problem facing the international community was Saddam Hussein's failure to co-operate with the UN.

He said: "That's the block, it's Saddam Hussein's, it's not the time, it's his attitude and his unwillingness to do anything.

"Unless they get some pressure on Saddam Hussein, Hans Blix will not be able to complete his task, as he has indicated today there is no co-operation, he cannot therefore verify whether those weapons have been destroyed or whether they still exist.

Threat

"That means his task is incomplete."

US Secretary of State Colin Powell told the Security Council: "Iraq has failed to comply with 1441. The threat of force must remain.

"Force must always be a last resort ... but it must be a resort.

"We can't allow this process to be endlessly strung out as Iraq is trying to do right now."

Words have to have meaning and the meaning of those words that if there is not the most full, active, substantive co-operation by Iraq then force would have to follow Jack Straw

Earlier on Friday, Prime Minister Tony Blair faced calls from one-time presidential candidate Reverend Jesse Jackson to hold face-to-face talks with Saddam.

Mr Jackson is due to address a peace rally in London on Saturday which organisers say could be the biggest demonstration the UK has ever seen.

Respect

He said: "I hope that Mr Blair, because he is a man who has engendered respect from so many people with his talents and his skill and his way of communicating, would do something as bold as go to Iraq and talk to Saddam face to face."

Reverend Jackson pointed out that there were other countries in breach of UN sanctions but "we are not threatening in any way to confront those nations militarily".

A spokesman for Mr Blair said that marchers had the right to protest but remarked similar rights were not currently enjoyed by the Iraqi people.

He added: "It's worth remembering that if people are saying 'stop the war', there is no military conflict at the moment."

Later several protesters marked Valentines Day by chaining themselves to the gates of Downing Street and urging the prime minister to "have a heart".

Paul Greening, who was one of those involved, said: "We're trying to get attention in a non-confrontational, light-hearted way but also with a very serious message that war is ridiculous, immoral, unjust and illegal."

The UN Council voted unanimously last November to send inspectors back to Iraq to look for weapons of mass destruction but now seems split over the need to use force to ensure disarmament.

	:	Who backs war?
Where key nations stand on Iraq

Nato remains divided over military action, after Germany, France and Belgium rejected on Monday a US request to bolster Turkey's defences on the grounds that it was a move to bring them into war with Iraq by the back door.

Anti-war rallies planned for this Saturday are expected in New York as well as London.

France, Germany and Russia, who all have seats on the current, 15-member Security Council, have said the inspections should continue.