David Blunkett's plan for compulsory identity cards will be condemned by MPs tomorrow as improperly costed, poorly thought out, secretive and "lacking in clarity both over the scheme's scope and practical operation".

The MPs, on the home affairs select committee, stress that they do not oppose ID cards in principle. But they express alarm about what they describe as "function creep" once a national identity register is in place. They warn that ministers are already planning to use the ID card scheme as a cover to introduce a national fingerprint system within five years.