Johann Hari: This strange backlash against CCTV

There is a danger that the debate about civil liberties is driven into a right-wing ditch

A month ago, I was walking back to my flat in the East End, which sits on that strange fault-line between the mega-wealth of the City and the mega-concrete slabs of Whitechapel poverty. It was a little after midnight, and my i-Pod i-solation was suddenly interrupted by a hoarse yelling. It's not strange to hear yelling here – but this was a man shouting: "I'm going to batter you, you fucking tramp! You homeless bastard! I'm going to kill you!"

A well-suited, well-booted City-boy was waving his fist and spitting hate at a terrified homeless guy, who was sitting helpless on the ground. Then there emerged a classic East End scene: a Bangladeshi, a Pole and a few lads from Devon tried to restrain the City-thug, telling him in a Babel of languages to calm down. Like an idiot, I tried to reassure the homeless guy by telling him I'd called the police – which prompted him to get up and try to run away. The man chased after him and kicked him into the road, screaming again that he was going to kill "the fucking tramp." He fell hard into the road, shivering.

As the police siren shrieked up to us, the City-boy broke off and the homeless guy disappeared, staggering, up an alleyway. The attacker then announced to the police that he was the victim here: the homeless guy had attacked him.

In many circumstances that would be the end of it. The victim had run off; there was nobody to show the attacker was lying. Except a police officer noticed there were two CCTV cameras nearby. When they were checked, it showed that this was indeed an unprovoked, vicious attack – and now the man is being prosecuted. He won't be able to keep on attacking the homeless.

This is a story that plays out, with mild variants, every day somewhere in Britain. Just to stick to the biggest headlines: the Ipswich Ripper was caught before he could murder even more young women because he was picked up on CCTV; the Soho nail-bomber was caught before he could blow up more black and gay people because he was captured on CCTV; and a few days ago at the Old Bailey, a man who shot a pregnant 22-year-old woman was banged up after being caught on camera.

In such cases, human liberty is enhanced by CCTV. There are women walking the streets of Ipswich and gay people walking down Old Compton Street today because CCTV caught somebody determined to kill them. When CCTV was introduced in a pilot scheme in Airdrie town centre in Scotland, over the following two years crime fell by 21 per cent.

Yet there has been a strange, inchoate backlash against CCTV over the past few years. When listing the real erosions of human rights carried out by the current government – the complicity with US torture flights, the restrictions on free speech to appease religious fanaticism, or the shipping-back of refugees to their deaths – CCTV often gets lumped onto the end of the list. Every act by a democratic state now seems to get reflexively opposed. There is a danger that the debate about civil liberties is being driven into a right-wing ditch where liberty will actually be undermined further.

Increasingly, the mood among the intelligentsia is that the only threat to liberty comes from the state – and the only way to advance liberty is to immobilise the state. But in reality there are two sources of threats to your liberty. One is indeed a government that could try to control and repress you. But the other threat – just as real – is from other people. The women of Ipswich were not being attacked by the state and its tentacles; they were saved by it from being killed in even greater numbers.

This isn't about "balancing" freedom against something else. It's about figuring out which mixture of state action and hands-off inaction will produce the greatest freedom in the real world.

This doesn't lend itself to grand, bombastic polemics warning that we have morphed into 1984. Instead, it requires a cool case-by-case conversation. But the critics of CCTV offer surprisingly few rational arguments to converse with. They warn gravely that if you walk through Central London you are picked up by nearly one thousand cameras. But you will only ever be picked up by a CCTV camera in a place where you could be seen by a random stranger. Walking through Central London, anyone can see you – and tens of thousands do. This isn't an intrusion into your privacy, because you aren't in private.

I am absolutely not saying that if you have nothing to hide, you have nothing to fear. I am saying that these cameras are not in places where you hide: they are in public, where you are being seen by any number of people you will never know.

The critics are left to conjure the prospect of a future totalitarian government that could abuse the camera systems. But if we had a totalitarian government, all sorts of things we need now would be menacing – not least the police and the Army. This is an argument against totalitarianism, not in favour of abolishing the police and army and CCTV just in case.

Of course beyond CCTV there are genuinely knotty debates, where the path to the greatest liberty isn't instantly clear. One has bubbled up again this weekend. The biggest abuse of civil liberties in Britain by far is the epidemic of unpunished rape, with 47,000 women being subjected every year. The setting up of a police DNA database in 2000 has helped to catch men who had raped thousands of women, and would have gone on to rape thousands more. So far, so good.

Then on Saturday, several senior police officers suggested that school-children who show the indicators of potential future criminality should be entered into the DNA database. Here, we become instinctively uncomfortable. Already, young black men are wildly disproportionately represented in the database because they are arrested so much more; singling out "problem" kids feels just as prejudicial.

I believe the solution that would most enhance liberty is to enter all newborn babies onto the database. That way, nobody is singled out unfairly, and random-rapists will be much more swiftly caught – and therefore will be able to rape fewer women. A tiny infringement of liberty has to be weighed against a very large one: a swab for all, versus a rape for many. I admit this DNA dilemma forces a real debate, and there are reams of reasonable people on the other side. But you cannot simply dismiss this tough choice, screaming "Totalitarianism!".

Of course we must always be vigilant about state power going too far; I oppose the actions of the state for great slabs of the time. But there is one thing that immediately kills any attempt to find the best road to real liberty: the closed-circuit paranoia that assumes any extension of state power is a sign of incipient fascism. It's time to stop shrieking about a police state at every turn, and start looking calmly and questioningly into the camera lens.

j.hari@independent.co.uk