LONDON -- Americans studying in Britain for more than three months will have to have biometric ID cards starting later this year.
Within three years, Britain's Home Office said Thursday, all Americans and other foreigners from outside the European Union will have to have the cards to work and live here.
U.S. tourists and businessmen and women who visit Britain for visits under 90 days will not need them.
But those seeking visas to marry a Briton and live here will have to have the cards starting in November, just like students, to prove who they are and that they are here legally.
About 250,000 Americans live in Britain, the U.S. Embassy in London has estimated. It's unclear how many Americans come to study each year.
British Home Secretary Jacqui Smith announced the requirement as she unveiled a new timetable for encouraging everyone, including British citizens, to carry the cards as a tool for combating identity theft, terrorism, illegal immigration and benefits fraud.
"We're all better protected if we can be confident that other people are who they say they are," Smith told the BBC.
Smith said British citizens working in airports and other areas vulnerable to terrorist attacks will have to carry the cards starting next year. She said she expected most Britons to have them by 2017.
She insisted that it wasn't mandatory to carry the cards all the time, but suggested doing so would be a convenience.
In addition to containing a digital photo, the cards will contain data that can be read electronically and matched against a computerized National Identity Register that will retain a cardholder's fingerprints and personal information.
The ID card program has been controversial, with many privacy advocates and political opponents of Prime Minister Gordon Brown's Labor government saying they are too intrusive and the government has no business keeping personal data on its citizens. It also has been plagued by delays in technology and rising cost estimates.
Foreigners' ID cards, which will be about the size of a credit card, will contain a digital photo and details of the cardholders' immigration status, whether they are allowed to work, receive government benefits and how long they can stay. It also will contain a "biographic footprint" of personal history and "biometric data" such as fingerprints on the cardholder.
In many ways, the card's requirements are similar to what Britain already is demanding of Americans and other non-European foreigners who apply for visas for extended stays.
At the end of last year, the British government began requiring visa applicants from the USA to provide fingerprints and a digital photo. Information on how long a visitor can stay and what benefits they can have already are on the visas, which are carried in a visitor's passport.
The ID cards have been promoted especially as a tool in cracking down on illegal immigration and in fighting terrorism. The Home Office estimates about 430,000 foreigners are living in Britain illegally. And Britain has suffered or broken up several terrorist plots in the last three years.
Smith pointed out that the British government already has issued 10 million passports to British citizens since 2006 that contain encrypted digital versions of the holder's personal information and a photograph on a secure chip. They are read electronically at borders.
But in the face of opposition to them, Smith sought to sell the cards as a benefit and convenience for Britons. She said they would help young people in applying for bank accounts and loans by verifying who they are.
David Davis, the shadow home secretary for the opposition Conservative Party, said the ID card program remains "dangerous."
"The National Identity Register, which will contain dozens of personal details of every adult in this country in one place, will be a severe threat to our security and a real target for criminals, hackers and terrorists," he said.
He also said the government has displayed a "legendary inability" to securely maintain people's personal data.
Last month, the government acknowledged that 1,000 laptop computers had been lost or stolen. In January, the Defense Ministry revealed that a laptop containing details on about 600,00 people interested in joining the British armed forces was stolen. And in November, the government admitted that it had lost confidential records for 25 million Britons who receive child-benefit payments.