The government wants to give law enforcement authorities greater access to information held by social networking sites amid concerns that terrorists are increasingly using them for communications.

The intention was announced by home secretary Jacqui Smith this morning in a speech to think tank the Institute of Public Policy Research as she highlighted the importance of communication interception.

"Our ability to intercept communications and obtain communications data is vital to fighting terrorism and combating serious crime, including child sex abuse, murder and drugs trafficking," said Smith.

"Communications data - that is, data about calls, such as the location and identity of the caller, not the content of the calls themselves - is used as important evidence in 95 per cent of serious crime cases and in almost all security service operations since 2004."

The government was already considering setting up a single database with information of UK citizens' emails, calls and web browsing habits, though is keen to emphasise it is information about the communications rather than the communications themselves that would be monitored.

This proposal was due to be put before MPs in the Communications Data Bill next month.

But Smith announced that she was delaying the Bill in order to expand its range of surveillance to include other non-traditional communication service providers.

Currently security and intelligence agencies can demand to see telephone and email traffic from traditional communications services providers such as ISPs and phone companies which store the personal data for business purposes such as billing, and voluntary agreements to do this already exist.

But new types of communications such as online gaming, social networking and media exchange sites also offer the potential for users to communicate, and be cause the services are free, providers have no reason to record use.

This is the information the security services want to be able to access and include in the database, potentially forcing these sites to record usage.

The Home Office says no decisions have been made yet and the government will be consulting on the issues in the New Year.