Chancellor Gordon Brown has backed the prime minister's threat that there could be war against Iraq even without new United Nations backing.

Mr Brown has largely kept quiet about the Iraq crisis, leading to speculation he might be distancing himself from Tony Blair's stance amid disquiet among Labour MPs.

Mr Brown might just spend a thought for the traumatised children of Iraq. Tam Dalyell

But as it was announced more troops and equipment are being moved ready for possible war, the chancellor said Saddam Hussein could not go "unpunished" if he defied the UN.

Mr Blair, who is meeting UN chief weapons inspector Hans Blix on Thursday, said he was confident the UN would back military action if necessary.

If one country did put an "unreasonable or unilateral" block on action, however, that could not be allowed to confine other nations, he said.

Defence Secretary Geoff Hoon has said already said Royal Marine commandos are to train in the Mediterranean, ready to go to the Gulf if necessary.

Mr Hoon announced on Tuesday that reconnaissance vehicles will soon be shipped out.

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Flights of Royal Marine "personnel" and other equipment will also begin shortly, said Mr Hoon.

The announcement means the entire infrastructure needed for eventual troop deployment is about to be moved to the Gulf.

Logistics troops have already arrived in Kuwait and now digging and heavy lift equipment, Land Rovers full of radio equipment and other engineering gear will be moved.

Defence officials insist no final decision on deploying a land force had been made.

Privately, they say that decision might be announced in the second half of next week.

Liberal Democrat defence spokesman Paul Keetch said the move make the public realise the seriouness of the situation.

More than 400 staff and students from a top UK health school have warned Mr Blair an Iraq war could cost half-a-million lives.

The group from the London School of Hygiene and Tropical Medicine pointed to estimates from charity Medact.

The charity predicts 260,000 people could be killed on both sides of a conflict, with another 20,000 lost in an Iraqi civil war and another 200,000 dead from the health effects of fighting.

On Tuesday, Mr Brown was asked if there could be a war against Iraq without UN backing.

He told GMTV: "There may be circumstances where that is necessary, but we still want to go through the United Nations."

Asked later to clarify what he meant, Mr Brown said: "If the international community asks for disarmament and that doesn't happen, he cannot be let off the hook and we cannot leave him armed."

Backbench unease

Mr Brown's public backing is seen as an important help for the prime minister, who launched a passionate defence of his Iraq policy on Monday.

Mr Blair will try to quell backbench fears when he addresses the Parliamentary Labour Party on Wednesday.

Veteran anti-war MP Tam Dalyell, told BBC Radio 4's World At One: "I think, quite frankly, we are being strung along and that they have made their minds up and that we had better recognise that fact."

Commons Speaker Michael Martin promised on Tuesday to hold ministers to their promise of a vote for MPs before action, unless to do so would endanger troops.