Facebook, Bebo, MySpace and other social networking websites could be monitored by the government in an attempt to tackle internet crime and terrorism.

The Home Office is considering plans to force such sites to hold data about their users' movements to thwart criminals who use them to communicate.

A European Union statutory order, called the Data Retention Directive, already proposes that internet service providers in member states store communications and traffic data for one year.

"That is one reason why the government are looking at what we should do about the Intercept Modernisation Programme (IMP), because there are certain aspects of communications which are not covered by the directive."

The IMP is a multi-billion pound project, which aims to build new databases capable of storing vast amounts of computer data as part of the fight against terrorism.