Millions of Britons who use social networking sites such as Facebook could soon have their every move monitored by the Government and saved on a "Big Brother" database.
Ministers faced a civil liberties outcry last night over the plans, with accusations of excessive snooping on the private lives of law-abiding citizens.
The idea to police MySpace, Bebo and Facebook comes on top of plans to store information about every phone call, email and internet visit made by everyone in the United Kingdom. Almost half the British population – some 25 million people – are thought to use social networking sites. There are already proposals under a European Union directive – dating back to after the 7 July 2005 bombs – for emails and internet usage to be monitored and added to a planned database to track terror plots.
But technology has moved on in the past three years, and the use of social networking sites has boomed – so security services fear that that has left a loophole for terrorists and criminal gangs to exploit.
To close this loophole, Vernon Coaker, the Home Office minister, has disclosed that social networking sites could be forced to retain information about users' web-browsing habits. They could be required to hold data about every person users correspond with via the sites, although the contents of messages sent would not be collected. Mr Coaker said: "Social networking sites, such as MySpace or Bebo, are not covered by the directive. That is one reason why the Government are looking at what we should do about the intercept modernisation programme because there are certain aspects of communications which are not covered by the directive."
In exchanges with the Liberal Democrat home affairs spokesman Tom Brake, he insisted: "I accept this is an extremely difficult area. The interface between retaining data, private security and all such issues of privacy is extremely important. It is absolutely right to point out the difficulty of ensuring we maintain a capability and a capacity to deal with crime and issues of national security – and where that butts up against issues of privacy."
Facebook boasts 17 million Britons as members. Bebo, which caters mainly for teenagers and young adults, has more than 10 million users. A similar number of music fans are thought to use MySpace.
Moves to include the sites in mass surveillance of Britons' internet habits has provoked alarm among MPs, civil liberties groups and security experts.
Mr Brake said: "Plans to monitor our phone and email records threaten to be the most expensive snooper's charter in history. It is deeply worrying that they now intend to monitor social networking sites which contain very sensitive data like sexual orientation, religious beliefs and political views. Given the Government's disastrous record with large IT projects and data security, it is likely that data will leak out of every memory stick, port and disk drive when they start monitoring Facebook, Bebo and MySpace."
Isabella Sankey, policy director at Liberty, said: "Even before you throw Facebook and other social networking sites into the mix, the proposed central communications database is a terrifying prospect. It would allow the Government to record every email, text message and phone call and would turn millions of innocent Britons into permanent suspects."
Richard Clayton, a computer security expert at Cambridge University, said: "What they are doing is looking at who you communicate with and who your friends are, which is greatly intrusive into your private life."
Chris Kelly, Facebook's chief privacy officer, said yesterday that it was considering lobbying ministers over the proposal, which he called "overkill".
A Home Office spokeswoman said the Government was not interested in the content of emails, texts, conversations or social networking sites. She added: "We have been clear that communications revolution has been rapid in this country and the way in which we collect communications data needs to change so law enforcement agencies can maintain their ability to tackle terrorism and gather evidence."