The United States and Britain are drawing up plans to give Iraqi President Saddam Hussein as little as 48 hours to flee Baghdad or face war, as part of a second UN resolution.

Such a resolution could be put before the UN Security Council by next weekend if weapons inspectors conclude in a key report on Friday that Saddam is still refusing to give up weapons of mass destruction, The Sunday Telegraph said.

But a Downing Street spokeswoman downplayed the report, saying: "It is far too early to be talking about that sort of thing.

"We are where we are and we need to let the inspectors get on with what they are doing before we start going down the road of what a resolution would look like."

The Telegraph quoted a senior UN Security Council diplomat as saying that Britain would put forward the resolution because Washington "does not want to be seen to need it".

"The resolution being discussed would declare that Saddam is in material breach of UN resolutions, which authorises the use of all necessary means to disarm him," the diplomat added.

The Observer weekly reported Sunday that Defence Secretary Geoff Hoon had launched a fierce attack on critics of Britain's tough line on Iraq, warning that some would not be convinced until a "missile with its weapons of mass destruction warhead is fired, or until terrorists are aided in carrying out an attack on one of our cities".

"The government is not prepared to sit idly by until hundreds or thousands are killed," Hoon said.

The Sunday Times reported that ministers were preparing to introduce a national network of air detectors to provide early warning of a biological attack by terrorists.

Mobile units, able to detect up to 30 different bacteria, viruses and toxins, would be deployed at public events, including state occasions and big sporting fixtures, the paper said.

Britain has been on terror heightened alert since the discovery of traces of the deadly poison ricin in a London apartment last month, which led to anti-terrorist police making a string of arrests.

The Times also reported claims that Iraqi forces attacked a Marsh Arabs' village in the Gandaleh area with chemical weapons in 1998, soon after UN inspectors left the country and several years after Saddam assured the UN Nations he no longer had weapons of mass destruction.

Baroness Emma Nicholson, the vice-president of the European parliament's foreign affairs committee, said she would present evidence of the attack to Hans Blix, the chief UN weapons inspector, this week.

Meanwhile, a YouGov poll for The Mail on Sunday showed that Prime Minister Tony Blair's approval rating had fallen in an indication of public unease about a looming war against Iraq.

The poll found that only 44 percent believed Blair was performing well, while 63 percent agreed with Nelson Mandela's recent criticism that Blair was more like the United States' foreign minister than the British prime minister.

The Independent on Sunday said in a front-page editorial that Blair had failed to produce a convincing case for war on Iraq.

"He asks us to trust him. We cannot do so," the paper said.