It is one year since Londoners awoke to a changed city. Suddenly, peace reigned and traffic moved. Bus passengers experienced the forgotten pleasure of overtaking pedestrians, while the stuff through which Londoners swim began to resemble actual air. It was the first day of the congestion charge. Ken Livingstone had taken on the car lobby -- and lived.

Opponents predicted gridlock around the charge-zone's perimeter, business bankruptcies, and a flood of outraged motorists. Instead, the scheme has been almost too successful. The plan was to use the charge to raise money for public transport at a rate of £200 million a year. But the drop in traffic has been so great, with 50,000 fewer vehicles entering the zone each day, that the first year's takings have produced only £68 million.

Now cities around the world are proposing similar schemes. And the Government, which greeted Livingstone's experiment with ominous silence, has welcomed him back into the Labour fold. At last, a transport initiative that works!

Traffic theory says that congestion is supposed to be self-adjusting: when it becomes unbearable people change their behaviour, by moving house or moving their job. But in real life, the unbearability appears infinitely distant, as people adjust to what might previously have seemed intolerable.

The problem is that one city is not a policy -- and especially not if that city is London. John Lewis reports a 9 per cent drop in trade, and Harvey Nichols, outside the zone, has extended opening hours to offset the negative impact: both blame the congestion charge. But London is not going to die commercially. Even within the zone, new shops continue to open.

Since most of the world's cities are choked by traffic, it is no surprise that others are planning similar schemes. Singapore, Rome and Melbourne already operate tolls; Edinburgh, Cardiff, Stockholm, San Francisco and Sao Paulo are considering them. All these are large centres that can be confident trade will hold up.

For smaller towns the situation is different. If Chelmsford, say, decided to charge for entry, people would simply take their custom to Colchester. The town might be quieter and cleaner, but it would also be dead.

It is no coincidence that the only non-metropolises levying entry charges are Durham, whose centre is ancient and tiny, and Norway, where tolls are levied in 20 towns and cities. If everyone charges, no one suffers disproportionately.

This, though, means that government must step in. And this government, like all its predecessors, will do anything to avoid offending the car-lobby. That is, us: nearly all Britons drive. On the other hand, 90 per cent of us live in urban areas, and would enjoy cleaner air and clearer streets as much as those who live and work in London.

In the 1960s, a group of campaigners succeeded in closing Washington Square, in Manhattan, to traffic. The city traffic commissioner forecast that surrounding streets would soon be swamped with cars. But, as in London, nothing of the sort happened: the cars just vanished.

The Government's avowed intention is to make us change our habits in this way. Will it pluck up courage and initiate an actual transport policy?

I am watching pigs for the first sign of wings.

Ruth Brandon is the author of 'Automobile: How The Car Changed The World', published by Macmillan

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