Britain is no longer sleepwalking into a surveillance state - the age of George Orwell's Big Brother is already upon us, or so government critics would have us believe.

Innocently walking down a street in Glasgow, Cardiff or London will mean a person's face is picked up by one or several of the UK's 4.2 million CCTV cameras. It is estimated that, on a normal day, someone's image will be captured more than 300 times.

Then, there are all the speed cameras on the roads, the proposed expansion of the DNA database, and the planned introduction of biometric ID cards.

A few years ago, Richard Thomas, UK Information Commissioner, warned that Britain could "sleepwalk into a surveillance society".

Yesterday, Nick Clegg, Westminster's champion of liberal democracy, announced we were already there. He angrily challenged Gordon Brown for creating a "surveillance state" and making the UK the "most spied upon on the planet".

He referred to 1000 surveillance requests a day, one million "innocent people" on the government's DNA database and the "scandalous"

fingerprinting of pupils in some 5000 schools.

Yet, there appears to be evidence it is not just the state that is spying on people but that we are beginning to spy on each other - a so-called "counter-surveillance society".

Michael Marks, director of Spymaster, a leading supplier of surveillance equipment, declared that bugging had become "a way of life" in modern Britain.

He admitted to not being surprised that Sadiq Khan, UK Government whip and Labour MP for Tooting in London, and his constituent Babar Ahmad, a terror suspect, were bugged while chatting across a table at Woodhill Prison in Milton Keynes.

Mr Marks claimed eavesdropping was now widespread and increasing. It was, he explained, used by everyone - from large companies trying to stay ahead of their competitors to worried wives checking on their wayward husbands.

"We are finding more people coming for counter- surveillance. Maybe they feel like they are being watched.

"One has to accept that there is a little paranoia involved but one can't deny the times that we live in," said Mr Marks.

Spymaster supplies about 40% of its equipment to the business world, while 20% goes to government departments and law enforcement agencies, which suggests the remaining 40% goes to individuals.

There is no industry association to keep track of the number of devices sold, but Mr Marks estimated the business in the UK was now worth hundreds of millions of pounds.

He said advances in technology, such as GSM, global system for mobile communications, were making surveillance easier to carry out. Investigators no longer need to park in a van outside an office to listen to a bug which had been planted; with GSM, they could eavesdrop from the other side of the world.

The Surveillance Studies Network (SSN), whose 2006 report for the Information Commissioner helped prompt a Commons inquiry, said that everyday life was "suffused with surveillance encounters" and the 4.2 million CCTV cameras represented one for every 13 people.

The gathering of personal data and information has become vital, with loyalty cards, credit cards, and even internet use able to be tracked.

The SSN report observed: "Most profoundly, all of today's surveillance processes and practices bespeak a world where we know we're not really trusted".