Human rights lawyers are increasingly alarmed that a piece of legislation that put state snooping on a legal basis has resulted in a huge expansion of the public sector’s ability to pry into private lives.

The Regulation of Investigatory Powers Act was not one of those pieces of legislation to grab the public’s attention when it was passed. But in Whitehall and among civil liberties groups, its importance was never in doubt.

The Act regulated surveillance and spying by police and the security services that had previously been operated merely by official guidance.

And once the Human Rights Act became law and with it the guarantee of a right to private life, Whitehall knew that guidance would be found inadequate by the courts. However, the Act was so widely drawn that eight years later, many state agencies have the right to spy on us.

There are three types of surveillance. Interception of communications — listening in to telephone calls, intercepting mail or planting bugs in homes or cars — is the most intrusive. The police, security services and Customs can use this technique but must receive authorisation from the Home Secretary or, in urgent cases, receive interim permission from a senior Home Office official.

The second type of spying, and the area causing most concern, is directed surveillance such as bugging, listening in or secret filming in public spaces.

Parliament agreed a big list to justify such surveillance, ranging from the obvious prevention and detection of crime to preventing public safety or protecting public health. Not content with these, MPs also handed the right to conduct such surveillance to a long list of government agencies, including 474 local councils.

The third type of surveillance is access to communications data, including the identities of those we phone and which internet sites people visit — though crucially not the content of the calls.

Initially Parliament only allowed organisations such as the police and security services the authority to access communications data but this was expanded to cover local councils and other public bodies.

Few people will object to them using surveillance to tackle crime, be it selling alcohol to under 18s or trying to catch people trading in counterfeit goods. Nor will many people be too worried if it is used against someone claiming benefit while working.

But the surveillance must be “necessary and proportionate” and it is those two words the critics say some local councils have forgotten. Is it really necessary to use such powers to deal with dog fouling or littering?

Civil liberties groups think councils are being heavy-handed. and the Act intended to provide protection for the right to privacy is now being used in a way that is infringing the right to a private life.

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