A large-scale army exercise is not part of direct preparations for war against Iraq, defence sources have told the BBC.

Newspaper reports on Friday suggested Exercise Log Viper, starting on Sunday by the Royal Logistics Corps, was putting major stockpiles of weapons and supplies in the right place for an operation against Iraq.

But one official told the BBC the equipment being transported to the Marchwood military port, near Portsmouth, was "all empty boxes".

By the time the exercise is over, nothing of any value will be ready to go anywhere, he added.

Deadline pressure

The purpose of the exercise was not to move real equipment, only to test the procedures involved in moving such equipment.

The manoeuvres came as the Daily Telegraph reported that advance parties of British troops would begin deploying to Kuwait within two weeks, in preparation for a possible attack on Iraq.

Tony Blair's stance against Saddam Hussein also received public backing from Chancellor Gordon Brown, who said the government "must have the strength to take the right decisions".

And at the UN, America is increasing the pressure for Iraq to be given a deadline for the return of weapons inspectors, with Secretary of State Colin Powell holding talks with members of the Security Council.

'Dismal truth'

Foreign Secretary Jack Straw said the threat of military action was the only way to get Saddam Hussein to accept weapons inspectors.

The "dismal truth" about the Iraqi regime, he said, was that it would not respond to international pressure unless it knew it risked being attacked.

In a speech to the UN on Saturday, Mr Straw will echo US President George Bush's words that the "authority of the UN is at stake" over the issue of Iraq and weapons inspectors.

"Those of us who believe in an active international community cannot stand by and do nothing while Iraq continues to defy the UN," he will say.

On Thursday, Mr Straw told the BBC there was "no question" of unilateral military action against Iraq.

Army manoeuvres

Exercise Log Viper is believed to involve 6,000 men - almost every member of the Royal Logistic Corps based in the UK.

It has been planned for a year and has been described as the largest such operation for many years.

The Daily Telegraph suggests the military is ready to go one step further - moving troops to the Gulf after a parliamentary debate on action against Iraq on 24 September.

It says attacks on Iraq by aircraft patrolling the no-fly zones will be stepped up in an attempt to force Saddam Hussein to give up his weapons of mass destruction.

Speaking to the Financial Times newspaper, Mr Brown said he fully backed Mr Blair's plans to deal with Iraq.

Mr Duncan Smith said the threat of force is needed

Questioned on divisions within the cabinet, the chancellor said: "I believe the government will act as one. I am not going to speculate beyond that."

He supported Mr Blair's efforts to help President Bush forge an international alliance, claiming Iraq posed too great a threat to ignore.

"The international community should not - and cannot - tolerate or leave unaddressed the issue of a regime that proliferates chemical, biological and potentially nuclear weapons in absolute defiance of international agreements," Mr Brown said.

'Military force'

On Thursday Mr Blair continued efforts to win support at home, revealing that his dossier of evidence against Saddam Hussein's regime will be published hours before the parliamentary debate.

He also met Tory leader Iain Duncan Smith and Liberal Democrat leader Charles Kennedy at Downing Street.

Mr Kennedy said he pressed the prime minister for a long parliamentary debate.

Mr Duncan Smith said MPs should be given a vote so they could send a strong warning signal to Saddam Hussein.