Today marks another important deadline in the US's stringent passport requirements for people from countries that are part of the Visa Waiver Program.

All passports issued after 26 October in VWP countries must contrain biometric data – however, people without the biometric chip shouldn't panic, as the US is still accepting passports issued before this deadline.

The Visa Waiver Program allows people from 27 countries to enter and remain in the US for up to 90 days for business or leisure without a visa.

Passports issued in the last 365 days must have a digital photograph that can be read by a machine; and those that were issued before 26 October 2005 must have a machine-readable zone.

Most European countries are in the VWP, as are Australia, Brunei, Japan, Singapore, and New Zealand.

Biometric chip contains an image of the passport holder that was created by face-mapping technology, as well as biological data. The UK Identity and Passport Service says that the biometric passports are the most secure ever issued here, but reports earlier this year suggest that they can be cloned successfully (see link at the bottom of the page).