The British government said Wednesday that it intends to grant the United States permission to incorporate an air force base in northern England into its proposed missile defense network.

Defense Secretary Geoff Hoon said that he had reached a "preliminary conclusion" that Britain should allow the United States to upgrade and use the Fylingdales base in North Yorkshire.

Hoon said that ballistic missiles in the hands of "irresponsible regimes" were a real threat to British security and it would be irresponsible for the government not to acquire a defense.

"It is the combination of ballistic missiles and the possession of these weapons of mass destruction, together with the demonstrated willingness to use these capabilities, that makes Iraq the most immediate state threat to global security," he told the House of Commons. "Elsewhere, if North Korea ends its moratorium on flight testing, it could flight test a missile with the potential to reach Europe and the United States within weeks."

Bush administration officials have said the United States must develop defenses in case a hostile country such as North Korea develops and fires a long-range missile at the United States. Critics have said the program -- scheduled to cost more than $7 billion this year -- is too expensive and the technology too uncertain.

The Pentagon hopes to have a permanent test site built in Alaska in four years that could provide some basic defenses for the project.

Hoon said the necessary upgrade of Fylingdales would be "an invaluable extra insurance" but did not commit Britain to any deeper involvement in missile defense. Such a decision could be made later, he said.

Fylingdales has operated since 1963 as a ballistic missile early-warning radar system, which together with other radars in the United States and Greenland provides tactical warning and attack assessment of a missile attack against Britain, North America or western Europe.

The United States is also seeking approval from Denmark to upgrade a similar radar complex at Thule Air Base in northern Greenland, a semiautonomous Danish territory. Danish Foreign Minister Per Stig Moeller said last week that the request would be answered in June.

Hoon told British lawmakers that the government has not replied to the U.S. request and that they would be given the opportunity to state their views in a debate on defense in parliament next week.

"But it is only right that the House should know the government's preliminary conclusion that it is in the U.K.'s interests to agree to the request," he said.

Bernard Jenkin, the defense spokesman for the opposition Conservative Party, welcomed the government's decision.

Hoon said the government planned to sign a deal with the United States that would give Britain full insight into the development of missile defense and the opportunity for British industry to benefit from participation.

But some lawmakers from Blair's Labor Party said the development of the system, dubbed "son of Star Wars," would undermine international arms control treaties.

"This slavish devotion to American policy in this area adds further to global destabilization," said Labor legislator and former defense minister Peter Kilfoyle.

Fellow Labor lawmaker and anti-war campaigner Alice Mahon said she had received hundreds of thousands of letters opposing U.K. involvement in America's missile defense system.

"It's absolutely dreadful that once again we acquiesce to President Bush's request, in opposition to the people who actually elected us."