Changes to passports are planned in the next few years

"Fingerprinting does not need the ID Cards Bill. No-one is forced to have a passport," the Home Office said.

As passports are issued by Royal Prerogative the change does not require new laws, but the Home Office stressed a decision had not yet been made.

Labour has said it will re-introduce ID card plans if re-elected on 5 May.

Digitised photograph

The plan to introduce fingerprinting is among a number of changes being considered for passports.

By the end of 2006, there will be face-to-face interviews for the 600,000 new applicants who come forward each year.

This will have been preceded in 2005 by the introduction of a microchip storing a digitised photograph.

The ID card scheme would cost an estimated �3bn and see each UK citizen issued with a "biometric" card bearing fingerprints and other personal details which would also be stored on a new database.

Opponents say that the plans will infringe citizens' privacy but ministers insist they will help tackle illegal immigration, organised crime and terrorist groups.

A Home Office spokesman said: "No final decision has yet been made on the inclusion of a second biometric such as fingerprints or irises in passports.