David Aaronovitch: If it helps, I'll carry an identity card

'If I'm rational, I have to accept that not only could it happen here, but that somebody, somewhere, probably has a plan for it'

I think some of us are in denial. It is as though the collapse of the twin towers 15 days ago was a natural disaster, an act of God, like a volcano or an earthquake – something that will almost certainly not happen again, but if it does, that we are powerless to prevent. As I watched the TV news showing New Yorkers buying gas masks, I felt that familiar prick of British condescension towards the panicky Yanks. If only they had been through what we, with our Blitzes and IRAs, have been through.

But this time they know better than us because they have had the impossible happen to them. How can you tell someone who actually saw the towers fall that they are over-reacting? After all, what would I have said, 16 days ago, to an office worker who refused to sit behind a desk in a tall building for fear that a hijacker might fly a plane full of people into it? That no-one would want to do such a thing, probably. What would be the point of a massacre like that? And anyway, it would take outrageous audacity, incredible planning and a vast amount of luck. So don't worry. Go to work. See you tonight.

On the 11th, all previous rules about what we in big Western cities can expect were torn up but some of us haven't got it yet. We might have been able to envisage such slaughter in Jerusalem because, whilst that was unbearable, at least it was proximate. Even at Omagh the Real IRA fascists who planted the car bomb didn't really mean to kill and mutilate schoolchildren or the occasional pregnant mum and they certainly didn't hang around in the car itself. Not when there were border pubs to sing patriotic songs and get pissed in.

Why do I somehow not quite believe that it could happen here? London and New York are two of the great trans-national cities of the West and I live and work in the heart of London. Why do I resist an imagined picture of standing on Parliament Hill and seeing the flames over the city, just as John Updike and others watched the World Trade Centre fall? It may be because I was eight during the Cuban missile crisis, and – as a child – fully expected one day to find the beautiful H-bomb cloud rising above the highest roofs. Then the Cold War ended and I felt safe from annihilation.

Now, if I'm rational, I have to accept that not only could it happen here, but that somebody, somewhere, probably has a plan for it. So what precautions can we take? After the Baltic Exchange bombs the City was sealed off for cars by the "ring of steel". The area is still covered by an array of cameras which scan car registration plates and check them with the DVLC computer. A series of station bombs saw the abolition of waste bins in London termini. Several acts were passed to allow the police more powers to intercept, search, hold, interrogate and pry.

But what about now? I find myself unworried by the prospects of chemical or biological terrorism or of the famous nuclear suitcase. My nightmare is about the effect on race relations in Britain were one or more suicide bombs to explode in Britain. I am not even going to hypothesise targets – you can do that for yourself.

Back in April 1999 a young suburbanite called David Copeland planted a bomb in a gay pub in Soho, The Admiral Duncan. There was no warning, and when it exploded three people, including a pregnant woman, were killed. It was Copeland's third bomb. He was caught later that week after police issued pictures taken on a CCTV camera at Brixton.

Copeland made me aware of three things. The first was how easy it was to make such bombs and to plant them, provided you were prepared to run the risk of blowing yourself up by accident. The second was just how rare such incidents are given the pleasure that the bombers get from playing God. And the third was how Copeland's acts made authoritarians of many of us.

In London the voting threshold for getting on to the new Assembly was raised, specifically to exclude neo-fascist groups. Ken Livingstone wanted to go further. "We must defeat them (fascists) using all the powers of the state," he said. And a few powers that the state did not yet have, since Ken wanted the Government to be given the ability to ban far-right organisations.

Copeland's case convinced me of the value of CCTV. It had been argued by some libertarians that spy cameras simply shifted crime and were the thin end of a state wedge. I noted that Newham, the first local authority to use digital face recognition system with its CCTV network, saw assaults in the borough fall by 21 per cent and burglaries by 39 per cent.

The events in America are now making me wonder about ID cards, especially "biometric" cards that can read unique characteristics (such as the iris) and thus be almost impossible to forge. I am, to say the least, unconvinced by some of the arguments against. "The terrorists will have won" line is just rhetoric – Osama bin Laden doesn't much care if we have ID cards. Those who argue that it will be ineffective find uneasy bed-space next to those who complain that it could be too effective; a compulsory ID system would surely make things more difficult for those moving illegally from country to country, or easier to track those under suspicion. More potently it is suggested that ID cards would be unpopular and destroy co-operation between police and public. Yes, but the same was said about compulsory seat belts, crash helmets and about speed cameras. And other countries like Spain seem to cope without reverting to Francoism. A bonus – in addition we could have organ donorship encoded on our cards and thus provide thousands of waiting transplantees with the fresh bits they need.

Of course it isn't as simple as that. Privacy International, a civil rights group, provides some splendid information on its website about why the attempt in the late Eighties to institute a compulsory Australia Card went belly-up. The planned enforcement of the card involved big penalties for employers employing uncarded people, big penalties for losing your card and not reporting it, big penalties for failure to produce the card at the Tax Office. A person without a card wouldn't have been able to draw money, buy or rent a home, claim unemployment or take widows benefit. A cardless person would become, effectively, a non-person. Worse, the Australian government was not open about the uses of the card, planning to start it off slowly and then to use "function creep" to add to its uses. A people who had been in favour of the card turned decisively against it.

As one professor has commented, there is a tendency, as governments have collected more information on their citizens, for those same governments to become more secretive about themselves. Suppose, however, that as we gave more dope on ourselves, the Government was to do the same? There is a Data Protection Act tribunal decision expected this week which may order MI5 to allow access to some of the files it has been keeping on citizens. Such access, added to a much more comprehensive Freedom of Information Act, might make for a quid pro quo between state and citizen. Same thing for a national DNA data base.

If it helps in the fight, I'll show you mine, if you show me yours.

David.Aaronovitch@btinternet.com