The foreign secretary has warned Cabinet colleagues that plans for compulsory identity cards are "flawed", according to leaked papers published on Sunday.

Jack Straw, who preceded David Blunkett as home secretary, also warned that the government could be "harmed" by any such move.

In a letter to Blunkett dated September 24 that was also circulated to others in Whitehall, Straw set out a series of objections to the plan.

"The potential for a large-scale debacle which harms the government is great," he cautioned.

"I believe the proposed plan is flawed and no tinkering with particular issues will be able to resolve what is a fundamental political matter.

"The potential for a large-scale debacle which harms the government is great and any further decisions on the next steps must be made collectively.

"I will continue to urge strongly that this be shelved."

According to the Sunday Times, a second letter from Treasury minister Paul Boateng said the home secretary should consider "alternative options that would provide us with a series of quick wins with much lower risk and costs".

Blunkett has been a strong supporter of moves to introduce ID cards, and he has also won support from the prime minister.

"It makes sense to ask whether now, in the 21st century, identity cards are no longer an affront to civil liberties but may be a way of protecting them," Tony Blair told Labour's Bournemouth conference.

However, a series of reports has indicated the Cabinet is split over the issue.

It is believed that Straw and chancellor Gordon Brown are leading the opposition, expressing concerns about the civil liberties implications, practicalities, effectiveness and costs of any such scheme.

Trade secretary Patricia Hewitt has also warned that ID cards raise "enormous questions" for civil liberties.