The British Prime Minister, Mr Tony Blair, said yesterday that Britain had to listen to US proposals for a missile defence programme, and Mr Blair's spokesman said the government broadly backed the idea.
"I believe President Bush has set out a case that we have to listen to," Mr Blair told parliament a day after Mr Bush said he wanted to replace the Anti-Ballistic Missile (ABM) treaty and build a new missile defence system.
Mr Blair stopped short of saying Britain would get directly involved in the scheme, which may require the upgrading of US radar facilities in northern England. "We will make our deliberations once we have had a specific proposal from the American administration," Mr Blair said.
But Mr Blair's spokesman, Mr Alastair Campbell, indicated the Labour government was generally well disposed toward the US plans. Asked if the government thought the US scheme was a good idea, Mr Campbell said: "Broadly, yes."
"The Americans are the last remaining superpower," he said shortly after Mr Blair's comments. "They are the only ones who can develop this technology, and they are going ahead with it."
Mr Campbell continued: "We support the Americans taking the lead in the assessment, the battle against what could be a real threat from different parts of the world." He added that Britain intended to remain "America's closest ally".
The latest US plan is opposed by Moscow and Beijing and is viewed with scepticism in Europe and within Mr Blair's own party.
President Bush confirmed on Tuesday that he would go ahead with the plan, although the ABM treaty has been a bedrock of US-Russian nuclear stability for 30 years.
Mr Bush said the 1972 treaty between Washington and Moscow needed to be replaced to permit a missile defence system to protect the US and its allies from attack from what they call "rogue" states or from accidental launches.
The former British prime minister, Baroness Thatcher, a vocal proponent of the original "Star Wars" system pushed by President Reagan in the 1980s, urged Mr Blair to back Mr Bush.
"I strongly support President Bush's plan to protect America and her allies from attack by ballistic missiles, and I trust that the British government will stop its shilly-shallying and support them too," she said.
But Mr Blair said he would wait until he received a "specific proposal" from the US before making up his mind. He added that US experts were expected to visit Britain next week to discuss their plans with British counterparts.
Observers point out that to say "no" to Britain's closest ally would be almost unthinkable. But a "yes" could bring trouble at home, including protests of the sort that went on for years at Greenham Common.
Western states are concerned about the US plan. President Chirac of France called it an "invitation to proliferation" while the German government expressed concern at the scrapping of the ABM treaty.
Russia insisted yesterday that the ABM treaty remained key to global security, but added that it was ready to discuss US defence worries. India, which has recently become a nuclear state, welcomed the Bush proposals.