It was a perfect day for a bit of news burial, and so it proved. On Tuesday, while everyone was chewing over Alistair Darling's mixture of gain and pain, a British government began issuing ID cards for the first time in 56 years, though few people seemed to notice. As well as a spread of quiet news coverage, a small group of cultural and political high-ups - Neil Tennant of the Pet Shop Boys, Brian Eno and Shami Chakrabarti, the director of Liberty - warned of the damage to the UK's image abroad, and there were small protests in Liverpool and Cardiff, but that seemed to be it.

Maybe the prospect of the Tories taking power and honouring their pledge to scrap the scheme has dampened the anti-ID camp's ardour. For now, however, the government's aim - should Labour win the next election - of introducing the cards and a national identity register by stealth, seems to be proceeding to plan. From this week, students from outside the European Economic Area and the non-European spouses of accredited British residents will need to apply for a card and go on the register. The same will soon apply to millions of other foreign nationals and airport staff; and by some time in 2012, every applicant for a new passport will be joining up.

From a panicky perspective, irrespective of what happens at the next election, it's not hard to see all this coming to pass thanks to the bureaucratic equivalent of the great German war machine - though if such comparisons suggest the state at its most clunky and Kafkaesque, the government is busy wrapping its ideas in shiny inclusive packaging. Last week, for instance, it announced that transgender people will be allowed to carry two cards at once.

So, the madness continues, and even people in power seem either confused or opposed. In the past few months I have spoken to one government minister who claimed the project had effectively been kicked into the long grass, and another - no leftie - who optimistically sketched out how the Brown government might have decisively served notice of lean times and a bold new direction: scrapping the renewal of Trident and calling time on the ID scheme. Fat chance, it seems. Jacqui Smith's zeal seems undimmed: the plan is becoming more concrete and the Home Office's cost projections are being vigilantly updated. In keeping with the fashion for optimistic government forecasts, it puts the cost of a newly combined passport-ID scheme at slightly more than £5bn over 10 years, though plenty of voices predict anything up to three times that amount.

Relative to the huge budgetary figures dancing before our eyes, that may still seem modest - but should you want to be mischievous with the official figures, it's not hard: £5bn is a quarter of what the government expects to take back before 2015/16 via tax rises. According to the Home Office's numbers, the annual cost of the plan will peak at about £525m - on today's figures, just over 75% of the yearly proceeds from the much-discussed 45% top tax rate. If the whole lot was brought forward, it would cover nearly two years of Labour's Building Schools for the Future programme.

Fiscal maths will surely inflame public opinion less than a more general complaint - that when times are tight this is exactly the kind of ill-advised cash magnet to avoid. If the era to come will be one of crackdowns on waste and anxious public audits, the Tesco mantra will be unanswerable: every little helps, and savings from the death of ID cards will be bigger than most.

Here, perhaps, is the most useful argument against the scheme, and the key to the fight to come - not elegant tributes to the glories of the Liberal inheritance, or invocations of the Big Brother state, or even warnings from the more enlightened end of the Groucho Club - but something altogether more blunt: we simply can't afford it.



john.harris@theguardian.com