Opposition MPs and civil rights groups have reacted angrily to recommendations by the Cabinet Office which would see personal data being shared across government departments.

The Performance and Innovation Unit, which reports directly to the prime minister, has called for changes that will allow departments to swap details such as medical records, tax information and benefits payments - possibly without the individual's knowledge or consent.

Other plans, which could be implemented over the next three years, include increasing data security and establishing a "trust charter" for information use.

Details of the move were contained in proposals aimed at delivering "seamless" services.

Information would be shared only in the interests of "national security, statistical analysis, protection of the national economy or the prevention of crime".

Conservative shadow home secretary Oliver Letwin said the move was a repeat of attempts to change the law which were defeated in the terrorism bill.

"We have very grave reservations about this move. We fought off attempts by the government to do something very similar under cover of the terrorism bill earlier in the year, and now we find that this was part of a plan to enlarge the scope for big brother throughout Whitehall," he said.

"We shall want to look very carefully and very sceptically at the details of any proposals."

Liberal Democrat civil liberties spokesman, Norman Baker, described the plans as "draconian, dangerous and undemocratic".

"This is an appalling, centralist suggestion. It drives a coach and horses though the rights and liberties of the individual," he said.

"Of course some data should be shared for good reasons such as national security but these are dangerous, draconian and undemocratic proposals. While some data-sharing may be necessary there need to be parallel safeguards but they are conspicuous by their absence."

Civil rights group Liberty also expressed unease. "It's a basic principle of data protection that personal information that we give for one purpose should not then be used for another purpose without consent," said director John Wadham.

The Institute for Public Policy research said the government had not gone far enough to protect privacy.

"The policy recommendations will be far more effective at improving data-sharing than they ever will be at building trust," said Ian Kearns, senior research fellow.

"What we need is more empowerment of the citizen in terms of control of data. This means a strengthening of the Data Protection Act and a more aggressive pursuit of privacy-enhancing technologies than the government is contemplating in this report."