UK citizens may be asked to carry smart cards carrying biometric information alongside conventional passports within four years.

Bernard Herdan, the chief executive of the UK Passport Service, said the proposals fitted in with plans by Home Secretary David Blunkett's to introduce an "entitlement" card, which critics see as leading towards compulsory ID cards. The two projects could end up being merged.

"That would be a big step, but many countries are considering it," he added.

The Passport Service wants to introduce passport smart cards, which would contain data on either an iris scan or fingerprints, by 2006. Many countries still require visas and entry stamps, so a paper passport would still be needed for the foreseeable future.

Since January 31, asylum seekers in the UK have been issued with biometric cards holding family details, nationality, date of birth and other information. ®