The ID cards plan has been controversial from the outset
Plans to introduce an ID card scheme in the UK have been branded "excessive and disproportionate" by government watchdog Richard Thomas.
The information commissioner said he feared the UK was in danger of becoming a "surveillance society".
He said civil servants would be able to build a picture of how every UK adult led their life.
He was speaking after Prime Minister Tony Blair said ID cards were an idea whose time had come.
Mr Blair said: "There are good reasons for doing this now, because of the change to technology, the fact that we will have to pay for biometric passports and the ID card part of it is a very small additional cost."
He added would drop the plans if the costs began to spiral out of control.
The ID Cards Bill is due back before MPs on Tuesday and Mr Thomas said MPs should consider the impact of creating a huge databank of personal details.
He said: "The measures in the bill go well beyond establishing a secure, reliable and trustworthy ID card.
"The measures in relation to the National Identity Register and data trail of identity checks on individuals risk an unnecessary and disproportionate intrusion into individuals' privacy."