The majority of the 27 countries that take part in the US Visa Waiver Programme have met the US requirement to introduce biometric passports equipped with RFID (radio frequency identification) chips.
Of the 27, which includes the UK, only Andorra, Brunei, and Liechtenstein have failed to start issuing the passports by the 26 October deadline.
Citizens from those three countries using a passport issued after this date will now have to apply for a visa to visit the US.
UK citizens have been issued with biometric passports since this March. Those with a passport issued without biometric chips can still get into the US without a visa if they have a digital photo and machine readable details in their passport.
UK citizens with passports issued before digital photos were introduced can still get into the US without a visa with a stick-in photo, providing they have a machine-readable passport.
The new biometric passports contain an RFID contact-less chip with the passport holder's biographic information stored on it, along with a biometric identifier, such as the digital photograph of the holder.
The US wanted the biometric passports to help fight terrorism and crime by making it more difficult to forge passports.
US Department of Homeland Security secretary Michael Chertoff said, “The department is committed to shutting down the ability of terrorists and criminals to use false travel documents to move freely through our borders. The upgrade to e-Passports is a significant advance in preventing terrorists from using lost or stolen passports to obtain entry into the US.”
The biometric passports carry an international e-Passport symbol on the cover and are said to have security features which prevent the unauthorised reading or ‘skimming’ of data stored on the chip.
But some security experts and privacy advocates have expressed fears that this data protection is not strong enough, and that criminals may soon be able to hack into the chips, even wirelessly from a distance, and steal the details.