The private correspondence of millions of people who use social networking sites could be tracked and saved on a “big brother” database, under new plans being drawn up by the UK government.

Ministers revealed yesterday that they were considering policing messages sent via sites such as MySpace and Facebook, alongside plans to store information about every phone call, e-mail and internet visit made by everyone in the United Kingdom.

"That is one reason why the Government is 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."

Rik Ferguson, a security expert at Trend Micro, the internet security firm, said: “The Home Office insists that this information is vital for fighting crime and terrorism; but is this legislation really going to be effective against the people at whom it is supposedly aimed?