The House of Commons will tonight consider a series of amendments to the ID card Bill. In the current political atmosphere, with the Government’s now 64-seat majority more notional than real, there is no doubt that we will have a week of high drama at Westminster.

To some dissidents, the issue of ID cards is one of principle. They oppose them in any form. For most people, however, the reservations are more a matter of practicality. The abstract ideal of free movement is already compromised by cameras on street corners. The typical wallet contains many forms of identification which can identify both an individual and that individual’s whereabouts, whether it be at a cashpoint or an Underground station. The theoretical concept of the citizen wholly independent of the state has long passed. If ID cards can provide tangible benefits at a tolerable cost, they would be acceptable.

There are two crucial votes which the House of Commons will deal with today, relating to amendments from the House of Lords. The first concerns whether, as the Lords would prefer, the Government should be obliged to produce precise costings for ID cards before it could begin to introduce them. This might seem a mere procedural device, but it is in fact a wrecking amendment. It is difficult for the Home Office to calculate exactly what the price tag of this initiative will ultimately be. There have been bizarre estimates by academics, determined to derail the ID card plan, but the general truth is that the cost of sophisticated chip technology is falling sharply, and the greatest expense is certain to be bureaucratic.

A far more relevant matter is the meaning of compulsion. The Labour manifesto of 2005 pledged that ID cards would occur on the basis of “rolling out initially on a voluntary basis as people renew their passports”. A normal person would, we think, believe these words to mean that, as individuals updated their passports, they would be invited, even encouraged, to opt in to ID cards — as they might wish. What the original Bill said, by contrast, was that anyone who wanted to renew their passports would have to submit their biometric and other data to the national identification register and thus have an ID card. It is a strange version of “voluntary” which makes ID cards “compulsory” if citizens wish to travel. MPs should back the language from the House of Lords that decouples passport applications from ID card applications as Labour’s manifesto implied.

It might be protested that this would emasculate the whole enterprise. But the language of the original policy is clear and the gradual introduction, voluntarily, of the cards will be a basis for compulsory issuance if the system works, and the cost is not unbearable. In the meantime, there needs to be both education and understanding: the Government should explain the need more coherently and openly; and the public should relax about a privacy issue that, in contemporary card-carrying Britain, is entirely irrelevant.