The Information Commissioner, Richard Thomas, said last week that he still had serious concerns over the adequacy of the government's plans to safeguard the public's data in the ID card programme, despite the introduction of tougher controls.
He called for the government to reassure the public by commissioning and publishing a privacy impact assessment of the programme, and granting stronger powers to the Information Commissioner to police the scheme.
Despite the government's attempts to clarify the purpose of ID cards, there were still many unknowns, making it difficult to assess whether the measures taken to secure data were proportionate, said Thomas.
"The technology is still at a fairly early stage of development. Most trials have been limited to a small-scale population. Moving to the full population does raise questions," he said. "We cannot afford to get this wrong."
Under the current plans, it was not clear whether police will be given the rights to access the data trails, retained to tackle organised crime and prevent terrorism, to investigate a wide range of other crimes.
"Will they have access to the database for murder, rape cases, unpaid parking fines. Where do you draw the line?" he said.
Thomas said that his concerns about function creep had still not been addressed, raising fears that the scope of the ID card scheme could be extended over time by future governments.
The Information Commissioner needed stronger powers to police ID cards, he said, calling on the government to give him the right to audit the scheme without seeking prior approval from ministers. This would provide him with a backstop, to ensure that the scheme was properly managed, he added.