Information commissioner Richard Thomas issued a strong response to the government's proposals last month.

While critical of the lack of detail in the consultation document, he said people should be in no doubt that 'we are dealing with matters touching on the very nature of the society in which we live'.

At the moment, he said, we live in a society in which 'the need to prove identity is commensurate with the service on offer'.But we could move to one in which 'the highest level of validation becomes the norm for the most mundane of services', with unique personal numbers used to track interactions with the state and others and to log these on a central register under state control.

Mr Thomas acknowledges that 'nothing so draconian' is currently planned but 'there is a potential for function creep as administrative and political priorities change, or even just to maximise the use of costly infrastructure'.

To prevent this, he says, tougher safeguards are needed including a commitment to using primary rather than secondary legislation to extend the reach of the scheme and a new statutory body to take charge of the register.