It has been disclosed that up to a million public sector workers could be allowed to access a Government database which would hold sensitive information on every child in England and Wales.

Critics of the database say that the figure is three times higher than ministers told Parliament, and ir increases priivacy concerns over the controversial ContactPoint system.

The database will contain the name, home address and school of all 11million schoolchildren in England and Wales as well as information about their legal guardians.

ContactPoint is designed to make it easier for public bodies to share information. Those permitted by law to access it include bureaucrats such as school administrators and any employee of a police force.

Campaigners fear that the greater the number of users, the more chance the database will be misused.

Phil Booth, of the NO2ID privacy campaign, said: ‘Rather than the 330,000 they have previously suggested – which was bad enough – it appears that a million or more people will be able to get access under the terms of the Children Act.

‘This, in the light of the Government’s own auditors saying that ContactPoint could never be made secure, paints a deeply disturbing picture.’

Baroness Sue Miller, a Liberal Democrat peer with a special interest in data protection issues, said: ‘The ContactPoint system was dubious to start with. It would have been irrelevant to key cases such as that of Victoria Climbie. This latest revelation merely makes it at least three times worse.’

Lord Adonis and Kevin Brennan, ministers for the Department for Children, Schools and Families, have informed both houses of Parliament that ‘the number of users (of ContactPoint) is estimated to be around 330,000’, but the legislation governing the database lists a some of the people who could potentially be granted access.  These range from senior police officers and headmasters to officers of local probation area boards and administrators working in schools or further education colleges.

Publicly available staffing figures from education authorities, the NHS, social services and other organisations show that the number of those falling into the categories listed by the Government is one million, according to the respected technology news website Register .

Both the Conservatives and the Liberal Democrats have pledged to scrap ContactPoint.

The DCSF later apologised for the breach of civil service political impartiality rules.

A spokesman for the department said: ‘Access to ContactPoint will be strictly limited to those who need it as part of their work and subject to stringent security controls. Not everyone who works in one of the roles listed in the regulations will be permitted access.

‘We have consistently maintained that the estimated number of users for ContactPoint is around 330,000, and this takes into account those needing access across all relevant sectors.