New government research shows that public authorities access nearly 1,400 private phone calls and emails each day.

The figures were revealed in the annual report of the Interception of Communications Commissioner and show that throughout 2008, public authorities made 504,073 requests to intercept the public’s communications, an increase of 44 per cent since two years ago.

This equates to the government snooping on the correspondence of one in every 78 adults.

The Liberal Democrats, who made the report public, said the numbers show Britain has “sleepwalked into a surveillance state”.

“It cannot be a justified response to the problems we face in this country that the state is spying on half a million people a year,” said Chris Huhne, Liberal Democrat Shadow Home Secretary.

“The government forgets that George Orwell’s 1984 was a warning, and not a blueprint. We are still a long way from living under the Stasi but it beggars belief that is necessary to spy on one in every 78 adults.

“The huge rate of phone tapping is all the more baffling when Britain is one of the few countries that will not allow intercept evidence in court, even in terrorist cases."

Public sector bodies have access to confidential communications data under the Regulation of Investigatory Powers Act (RIPA), which was granted to help the government fight the threat of terrorism

A Home Office spokesman said, “These powers can make a real difference in delivering safer communities and protecting the public — whether enabling us to gain vital intelligence that will prevent a terrorist attack, working to tackle anti-social behavior or ensuring that rogue traders do not defraud the public.”

He added that to ensure the effective use of RIPA, the Home Office has completed a public consultation on revised Codes of Practice detailing who should be allowed to access the data under RIPA and why.