"The risk of failure is significantly increased because there does not seem to be any firm and fixed statement of what the system is meant to achieve, what success or failure criteria are imposed and what scope limitations have been imposed," the BCS said.
The society warned that managing a big database and system such as that proposed by the national identity card bill would be "extremely complex and prone to error".
The BCS is also concerned that the project does not seem to link to other work on identifying people, as proposed by e-government initiatives.
"The two systems may not be fully compatible or mutually consistent," the BCS said. "If the system is to retain its credibility, it is imperative that it is demonstrably reliable, secure and accurate."
The problem of proving identity at registration is raised by the fact that children will not have ID cards until they are 16. "The BCS questions this on the grounds that unless people are identified at birth, or at entry to the UK if born overseas, it is quite difficult to prove their identity later," the inquiry was told.
Disabled people are among those that may have problems complying with the legislation, according to the BCS. "The draft bill says citizens must supply biometric information on request. This may not always be easy, not only for the disabled, house-bound or institutionalised members of society, but also for country dwellers who do not have easy access to transport," it said.
"The BCS suggests provision for people who are housebound or infirm, and also those who are unable to drive, people who cannot leave their livestock, for example, during spring lambing, and people who cannot afford public transport."
Data accuracy was another issue highlighted by the BCS. "Incorrect data would constitute a very serious matter for the citizen involved," it said. The legislation should therefore make specific provision for the detection and correction of errors which may arise. A formal process should be created, whereby the citizen confirms, on a regular basis, the correctness of the stored information. This process should be free of charge."
Concerns about the release of information from the identity register without the person's consent were also raised by the BCS.
"This information can be released not only to a wide range of people but also to those requesting verification of identity, if any of the facts they quote is in error," the BCS said. "This seems to introduce a process weakness which could result in the release of information to an enquirer who supplies incorrect information.
"Any release of personal information without consent or notification should be subject to stringent control and restricted to security authorities and others empowered under the Regulation of Investigatory Powers Act."