Philip Hensher: The state wants to know what you're up to. But why do we let it?

(PA)

Look up. If you're reading this in a public place in Britain, someone is probably watching you. A camera lens, pointing in your direction, recording you in case you do something out of the ordinary, something suspicious, something that isn't in accord with the camera installer's idea of normal respectable behaviour. No one knows how many CCTV cameras have been installed in Britain in recent years. It certainly runs into many millions, and is certainly more per head of population than any other society in the world.

The Government came into power suggesting that it was opposed to what, in a conference speech of 2009, David Cameron called the whole rotten edifice of Labour's surveillance state. But there is no prospect at all of it seeking to reduce the number of CCTV cameras and it has described them as a valuable tool in combating crime. Certainly their use is spreading and the detail with which they carry out surveillance of our private existences is on the increase.

In recent days, Oxford City Council has unveiled a plan to make video cameras mandatory in all licensed taxis by 2015. The cameras will not only record images, but, routinely, all conversations between passengers. A council spokesman said that the risk of intrusion into private conversations has to be balanced against the interests of public safety, both of passengers and drivers.

Interesting, isn't it, that use of the word balanced? If you counted the number of serious crimes committed in Oxford taxis and then the number of journeys made in Oxford taxis in the course of one year, then you might be able to come to a balanced view. Does this justify intruding on the private conversations carried out between every innocent passenger? A real sense of balance would surely say not.

But what balanced means, in this context, is what a three-year-old means by fair on Christmas morning. It means I think I ought to get whatever I want. The effectiveness of CCTV has been tested over and over again, and found to be grossly wanting. According to Big Brother Watch, in one London borough, Havering, CCTV footage was used just three times by police as evidence. Four hundred crimes had, in that year, taken place on local buses. The Metropolitan Police's own figures, analysis by civil liberties groups has shown, suggest that £20,000 is spent on surveillance equipment for every crime it helps to solve.

It's worth pointing out that this expenditure doesn't arrive from nowhere. It comes from crime-prevention budgets, which for a long time have been eaten up by CCTV initiatives. Between 1996 and 1998, three-quarters of crime-prevention budgets were spent on CCTV cameras. A Home Office review shortly after this boom period found that CCTV cameras had a tiny positive effect of 3 per cent improvement in public places, no effect whatsoever on crimes committed on public transport and a substantial improvement in multi-storey car parks. Was the moral drawn that they could be best used in some places, and not in others? Take a guess.

Other studies regularly show that the effects of security cameras decrease quite quickly over time, as people get used to the presence of CCTV on the Tube, and simply stop seeing them. Has that discouraged the steady increase in their numbers on all forms of public transport, including private taxis? You bet your sweet bippy, it's done no such thing. Other reports suggest that the simple step of improving street lighting in public places can lower crime figures by 20 per cent – a figure that does not diminish over time. But, of course, that seems like much less fun to a babyish council like Oxford's than filming and recording innocent passers-by.

Those concerned would, of course, dispute that the back of a taxi is a private space at all. But we all have a reasonable expectation of privacy, however public the place. To stand on a railway platform is not to surrender all rights to a private life.

The points on which the authorities now deem it appropriate to intervene in our private spaces are so many and varied as to make you wonder what the unifying motivation really is. The British Medical Association now argues that smoking in cars should be outlawed to protect children. Not outlawed when children are in the car: outlawed altogether.

Other members of the medical establishment have gone even further. A Dr Tony Jewell has called for parents to be banned from smoking in their own homes, describing it as the final piece of the protection picture. The desire to protect children from smoke is laudable. But how many people, seriously, smoke in their cars with the windows shut with children in the back seat? What balanced approach requires the forbidding, by law, of what must mostly be a private activity, and, without any doubt, the establishment of further powers of surveillance and control in that private arena to ensure conformity?

The truth is that what is driving these diverse attempts to introduce surveillance, based on such very different social issues, is not any serious attempt to diminish an evil. Most research shows that surveillance alone doesn't have a cost-effective result in general and that it often diminishes in effectiveness quite quickly over time. There are less intrusive, much cheaper remedies which have been shown to have more effect. So what is driving a council to decide to record private conversations, for doctors to propose that the Government should inquire into and prevent a private habit in a private place?

Simply, the desire to control and subjugate. With the mantra that "If you've nothing to hide, you've nothing to fear," the authorities have created a world in which it seems normal for some pathetic local authority to record your private conversations, to go through your bins, to inquire into what you do behind your front door in the evening. All we have left is the response that it's none of your business. I wish there was some less feeble response to this constant, exhausting, draining surveillance we live under.