Conservative Party leader Iain Duncan Smith says he supports a pre-emptive US offensive against Iraq because he believes Britain is on Saddam Hussein's list of targets for a missile attack.

Mr Duncan Smith - in an article in the Sunday Times - accuses the prime minister of failing to explain why Iraq's missile programme represents a growing threat to the British people.

Tory leader has warned of missile threat before

The Tory leader believes the next generation of Iraqi missiles will be able to reach the whole of Europe and writes that "we can choose to act pre-emptively or we can prevaricate".

Meanwhile, Tony Blair said the world could not stand by while Iraq was in "flagrant breach" of United Nations resolutions, as he arrived in Mozambique ahead of an appearance at South Africa's World Development Summit.

The prime minister insisted no decisions on how to tackle Saddam Hussein's regime had been taken, but added: "Doing nothing about Iraq's breach of these UN resolutions is not an option."

It has been confirmed that Defence Secretary Geoff Hoon will spend six days in the United States later this month and will be briefed by the US defence secretary, Donald Rumsfeld.

'Right for British people'

Mr Hoon is regarded as one of the most hawkish ministers in the cabinet and after being told of America's plans he is expected to outline options for possible British military assistance.

Mr Duncan Smith has warned before of the danger to Britain posed by missiles being developed by rogue states like Iraq.

Blair said doing nothing was not an option

Eighteen months ago, when he was defence spokesman, he promised the Conservatives would support an American ballistic missile defence programme.

Now as party leader he has stepped up that warning, convinced Britain is on Saddam Hussein's list of ultimate targets.

Mr Duncan Smith accused Tony Blair of allowing the argument in favour of a pre-emptive strike against Iraq to drift over the summer.

He said: "It is now time for the prime minister to explain to the British people what he already knows - that Iraq is a clear and growing danger to Britain."

International law

"The next generation of Iraqi missiles will be able to reach the whole of Europe. Saddam is just as likely to use terrorists to deliver such weapons," he added.

Conservative chairman Theresa May has also urged Mr Blair to "clearly set out the case".

"He knows Iraq poses a clear and growing danger to Britain," she told the BBC's Breakfast with Frost programme.

The prime minister would have her party's support if he committed Britain to military action, she said.

As well as a lack of international support for action against Iraq, there has been growing opposition from British MPs.

Defiant: Iraq is trying to bolster support

Former deputy leader of the Labour Party Lord Healey went as far as warning that the prime minister risked losing the leadership of the party if he supported a US attack.

But Foreign Secretary Jack Straw has said Parliament would be recalled if the cabinet made any decision about supporting US military action.

He added Britain would only get involved if the conflict did not breach international law.

European Union foreign ministers meeting in Denmark have agreed that Iraq must "immediately" allow UN weapons inspectors back into country to ascertain whether there are weapons of mass destruction or not.

Iraq 'not Afghanistan'

Iraq, meanwhile remains defiant, warning the US that its efforts to unite opposition forces and depose its president will fail.

Iraqi Vice-President Taha Yassin Ramadan said on Friday that "Iraq is not Afghanistan" - an apparent reference to the successful US strategy of backing Afghan opposition forces to overthrow the Taleban.

The vice president was on a four day visit to Syria and Lebanon, where he was hoping to bolster opposition to US war threats against Iraq.

Iraqi Foreign Minister Naji Sabri also joined the diplomatic drive, winning strong backing on a visit to China, a permanent member of the UN Security Council.