The cost of buying a new identity card could rise to £100, the Government has admitted as it presses ahead with the scheme.
The Government has put the running cost of the scheme at £5.8bn over its first 10 years - nearly twice earlier projections.
It suggested a charge of around £93 would be imposed on adults who receive ID cards with renewed biometric passports - an increase on the £85 estimated six months ago by David Blunkett, the former Home Secretary.
However the £93 "unit cost" figure was calculated at 2005-06 prices, suggesting it will reach £100 when cards are rolled out in 2008.
The Home Office has also revealed results of a pilot project, during which the fingerprints of 10,000 volunteers were taken along with a digital scan of their faces and pictures of their irises. All three biometric "identifiers" are likely to be included on the cards.
The project discovered the facial verification system - which measures the distance between features - took satisfactory images in 69 per cent of cases. Fingerprint verification was successful in 81 per cent of the sample. Iris verification worked in 96 per cent of trials, although there was a lower success rate for black people and older people.
But ministers stressed the trials were not testing the technology that would transfer the images to a national database.
Critics complained that the legislation left many important questions unanswered - particularly over the technology used to store records of fingerprints, irises and faces - and warned the cost of running the scheme was rapidly rising.
The ID card Bill ran out of time before the election in the face of entrenched opposition in the Lords and, with Labour's reduced majority, it could run into trouble in the Commons.
The Government has not substantially altered the Bill although it has given extra powers to the ID Cards Commissioner who will oversee the scheme. The Bill will receive its second reading next month.
Charles Clarke, the Home Secretary, met potential Labour rebels last night in an attempt to reassure them that the scheme would be foolproof against abuse. The Bill will be opposed at all of its stages by the Conservatives and the` Liberal Democrats.
Urging MPs to back the scheme, Mr Blair said: "The abuse of identity actually costs this country billions of pounds a year. We have the new biometric technology. We have in any event to move to new biometric passports as a part of other changes happening around the world."
But Mark Oaten, the Liberal Democrat home affairs spokesman, said the cost of the scheme was spiralling "out of control". He said: "Support for these plans will drop off very quickly when people realise the costs involved. The failure rates in the biometrics pilot are astonishing. The Government is spending our money on a half-baked scheme, based on half-baked technology."
David Davis, the shadow Home Secretary, said: "When the ID Cards Bill was introduced before the election, we decided it would be right to give the Government the opportunity to meet the concerns we raised. They have had six months to do so but today said the Bill was, in essence, the same one as before."
How much, precisely, will ID cards cost?
The Home Office, which has a history of revising estimates upwards, now says the "unit cost" of an ID card/passport will be £93 at 2005-06 prices. It says that is not necessarily how much people will pay, although the price is likely to be within a few pounds.
How much will it cost to set up the scheme?
The Home Office refuses to say, citing commercial confidentiality.
When will ID cards be made compulsory?
Previous Home Office estimates ranged from 2010 to 2013, but it now refuses to speculate.
How much impact will ID cards have on organised crime and fraud?
The Home Office say it is impossible to predict.
How can the technology be guaranteed 100 per cent foolproof?
Tony McNulty, the Immigration minister, only says it is "substantially in the right direction". Previous experience with government computer systems has not been promising.Reuse content