British Defence Secretary Mr Geoff Hoon said Britain needs to guard against the possibility of biological attack in the aftermath of last week's terrorist bombings in the US. And the newly elected Conservative Party leader, Mr Iain Duncan Smith, warned that the terror groups responsible might direct future outrages against the United Kingdom.
Their warnings came as the British Prime Minister, Mr Tony Blair, prepared for face-to-face talks with President Bush in Washington tomorrow evening.
Mr Blair will discuss the international situation, and review the Northern Ireland peace process at a breakfast meeting in London with the Taoiseach, Mr Ahern, this morning. The Prime Minister will then travel to Germany for his pre-planned meeting with Chancellor Schr÷der and from Germany to Paris for talks tomorrow with President Chirac.
From Paris Mr Blair will fly to Washington for talks and dinner at President Bush's request, before visiting New York en route to Brussels for Friday's emergency meeting of EU leaders.
Yesterday, Mr Blair continued his efforts to build worldwide support for the plans now being advanced by the Pentagon - holding "useful and constructive" talks by telephone with the Chinese President, Mr Jiang Zemin.
As the Home Secretary, Mr David Blunkett, prepared to meet his opposite numbers tomorrow in Brussels to consider the possible harmonisation of EU laws on extradition, a Downing Street spokesman said of Mr Blair's ongoing diplomacy: "Obviously it is important that we build the maximum consensus ... not just in terms of condemning what has happened, but also in agreeing the need to act against mass terrorism."
Amid growing expectations of a strong British military commitment to any American initiative, and evident unease within Labour's ranks, Downing Street continued to stress that the campaign should be undertaken in "a calm and measured way".
Specifically Number 10 did not choose to echo President Bush's declaration that he wanted to see chief suspect Osama bin Laden taken "dead or alive". Asked about Mr Hoon's suggestion of a possible chemical attack on Britain, the spokesman said the government did not believe terrorists had acquired that capability, but believed they aspired towards it.
"We have to realise the seriousness of the threat posed by mass terrorism. What New York and the Pentagon showed was that these people do not respect human life. A continuous process of threat assessment is carried out by our services, and that will continue."
Mr Hoon signalled that reassessment on BBC Radio 4, saying: "The scale of these attacks and indeed the fanaticism displayed by the perpetrators means that we have to think again about how we respond to these kind of threats."
Asked how realistic he thought the threat of chemical attack was, Mr Hoon replied: "It's certainly something we have to guard against. I believe the appalling events of last week have certainly caused us to think afresh about the preventive actions we need to take." Britain, he said, would need to re-think its approach to airline security as British Airways and Virgin Atlantic chiefs met the Trade and Industry Secretary to discuss this and the state of the country's airline industry.
In his latest intervention Mr Duncan Smith called for "restraint, in the sense that we don't commit ourselves to military action until it is necessary" while saying the government must ensure troops were prepared for action when intelligence indicated it was needed.
"We are a target just as much as America," said the Tory leader, "and we should recognise that protecting British citizens is about both offensive and defensive actions." As concern built about a number of attacks on the Muslim community across Britain, meanwhile, Mr Blair again insisted Muslims should not be blamed for the terrorist outrages in America.
Three men were arrested on suspicion of grievous bodily harm in a racist attack which left an Afghan taxi driver paralysed on Sunday morning in Twickenham. They were bailed until 25 September. A 19-year-old Asian woman was treated in hospital after being beaten around the head with a baseball bat in Swindon, while a "suspect" blaze at the Alvia mosque in Bolton, Greater Manchester, followed graffiti attacks on a number of other mosques.
London Mayor Mr Ken Livingstone asked the Metropolitan Police commissioner to keep him informed of plans for the safety of Arab, Asian, Muslim, Sikh and other vulnerable communities.