A leaked Home Office strategy document showed young people would be targeted from 2010 - the date originally set for the extension of the scheme to anyone renewing their passport.

That move, according to the report prepared in December for senior Whitehall officials, has now been put off until 2012 - after the last possible date for the next general election.

Instead the "first priority" would be to issue cards from next year to those in "positions of trust", the report said, with airport workers singled out for specific attention. "Alongside this we should issue ID cards to young people to assist them as they open their first bank account, take out a student loan etc," it continued.

Under the Government's 2006 action plan, it had originally envisaged that it would "issue significant volumes of ID cards alongside British passports by 2010".

The Tories, who oppose the ID card proposals, said the delays showed the entire scheme was now in "intensive care" and should be scrapped. And they attacked what they said were attempts to use students to introduce the cards by stealth - warning it could also be extended to cover public sector workers.

Shadow immigration minister Damian Green said: "This is an outrageous plan. The Government have seen their ID proposals stagger from shambles to shambles. They are clearly trying to introduce them by stealth by making them necessary if you want to work for the Government, take out a student loan or open a student bank account. This is straightforward blackmail and a desperate attempt to bolster a failing policy."

Although it refused to comment directly on the leaked report, the Identity and Passport Service insisted: "We have always said that the scheme will be rolled out incrementally."

The Home Office confirmed that "a date has not been fixed" for a full rollout alongside passports and that there was "always a degree of caveating" in the dates given. Prime Minister Gordon Brown's spokesman added: "The position remains as set out in December 2006. No decisions have been taken by ministers otherwise."

The biometric cards are due to be introduced for foreign nationals later this year, with the first expected to be issued to UK citizens on a voluntary basis from 2009.