In the first letter, Foreign Secretary Jack Straw calls the plan "flawed", while in the second, chief secretary to the Treasury Paul Boateng says "there may well be alternative options that would provide us with a series of quick wins with much lower risks and costs."
The scheme has always been controversial. A public consultation last year found most respondents opposing the Government's plans for compulsory ID Cards, dubbed 'entitlement' cards, which would probably incorporate biometric data.
The two letters were leaked to the Sunday Times, and give reason to suggest that ID cards will not now be the subject of legislation over the next Parliament, or even during the lifetime of this Government.
Straw stated, "I believe the proposed plan is flawed, and that no tinkering with particular issues will be able to resolve what is a fundamental political matter". He went on:
"How will we get people to accept a fee when asylum seekers get the card free? What about the practicality of ensuring every citizen provides a biometric sample while no effective procedures are in place for those who refuse? 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 issue be shelved."
Paul Boateng's letter focused on the monetary issues, pointing out that, "the charge for the card may be classified as a tax by the Office for National Statistics." The Government is planning to set a compulsory charge of £40 for each card, with a reduced fee of £5 for those on benefits or retired and under 75.