Those freedom-toting liberals, the Dutch, have invented a security camera designed to film and record not only the content of a conversation but also its tone. It has taken boffins at the University of Groningen a decade to teach the camera the difference between the noise of a car horn and an abusive hooligan shouting a string of expletives. The camera has just undergone a two week trial in a busy city centre street in Glasgow.

Good luck to it. The average Glaswegian can make a solicitous inquiry about the health of one’s grandmother sound like a challenge. It is the only city in the world where the words “all right, pal?” are invariably followed by a head-butt. Aggression is to the west coast male what oxygen is to the rest of us.

Actually, it’s not just the west coast male. It’s almost impossible to walk down any street in any Scottish town these days and not hear aggressive, abusive language from both sexes. It’s a generational thing. It sometimes seems that everybody under 30 is auditioning for a part in the Jeremy Kyle Show. Kids have always been high-spirited but now there is an added menace in their tone.

I blame soap operas. Everything from Hollyoaks to EastEnders sounds as if it has been scripted by the late John Osborne. Nobody talks civilly to anybody else on prime-time television. All discourse comes in short confrontational bursts. So the Dutch camera has its work cut out. The idea is that when the camera picks up aggression, it swivels in the direction of the noise. What happens after that is not clear. Presumably it takes the same mostly useless images as the other 1,982 cameras in Scotland.

The usual objection to CCTV cameras is that they erode our civil liberties and that we now live in a surveillance society.

Much is made of the fact the average person is recorded on camera 300 times in a day. Earnest types warn us that Big Brother is watching us. My beef with Big Brother is that he seems to be wall-eyed. Far from the Orwellian nightmare portrayed in 1984, Big Brother is singularly inept. It was the 1994 Home Office document “CCTV: Looking out for you” which paved the way for the proliferation of cameras in Britain. In the 15 years since, they have spread more rapidly than chickenpox at a nursery school.

The tiny fishing village of Elgol on the island of Skye got one last July, much to the bemusement of the gulls. It is incongruously attached to a fisherman’s bothy, permanently surveying a jumble of haar-shrouded lobster creels.

Proponents of CCTV argue that results can be impressive. Crime in Paisley’s Underwood Road is reputedly down 84% since cameras were installed, though how much of that crime has simply shifted down the road is a moot point. Steve Wright, who murdered five prostitutes in Ipswich, was convicted in part on the strength of CCTV footage of his car. Nobody can forget the harrowing CCTV images of Jamie Bulger being led away from a shopping centre.

Police claims of spectacular improvements in crime rates as a result of CCTV need to be taken with a lorryload of salt. Jason Ditton, director of the Scottish Centre for Criminology, says that many evaluations are “wholly unreliable”. The British Journal of Criminology describes the CCTV statistics as “post hoc shoestring efforts by the untrained and self-interested practitioner”. In neither the Wright nor the Bulger case did the camera prevent the crime. It merely helped get a conviction that arguably would have been achieved equally well by traditional policing.

If ever there was proof of Ludwig Mies van der Rohe’s maxim “less is more”, it is CCTV cameras. The more there are, the less effective they prove to be. According to Detective Chief Inspector Mick Neville, head of the Visual Images, Identifications and Detections Office at New Scotland Yard, only 3% of crimes are solved by CCTV. CCTV is no longer a deterrent because criminals assume, rightly usually, that they aren’t working. When they are working, police officers cannot be bothered trawling through hours of poor images in the hope of getting a lead.

According to Neville, “billions of pounds have been spent on kit but no thought has gone into how the police are going to use the images and how they will be used in court”. It is an astonishing admission from Britain’s leading police expert on CCTV. A report last year by the Taxpayers’ Alliance put the cost of British CCTV cameras at £500m. The market is currently growing by between 15% and 20% annually.

That money doesn’t merely represent a waste of taxpayers’ resources but also lost opportunities. It is millions that might have been more usefully spent on crime prevention methods with a proven track record, such as the recruitment of police officers. Alex Salmond caved in to pressure from Annabel Goldie last year and found an extra £8m to fund his promise of 1,000 extra police officers for Scotland. If these figures can be extrapolated, the money spent putting CCTV on fishermen’s bothies could have paid for tens of thousands of police officers.

CCTV cameras solve 3% of crime. Police officers have solved considerably more. They have the added advantage that it doesn’t take a bunch of academics 10 years to teach them the difference between an aggressive criminal and a car horn.

gillian.bowditch@sunday-times.co.uk

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