London's latest terror attack proves once again that we need to give streets back to the people

Soon after the invasion of Iraq in 2003, the street furniture around Westminster transformed into street armour. The Houses of Parliament were regarded as a trophy target for terrorists. An ugly ribbon of steel and concrete sprang up, aimed at preventing a suicide bomber with a truck bringing carnage to the heart of London.

The loser who set out intent on mass murder at Westminster used instead a weapon as commonplace as it is deadly: a car, driven at speed into crowds of tourists and Londoners. They were the softest of targets.

As a city, as a nation and as a world, we must accept that those who seek to trample on our liberal, open and tolerant way of life will turn increasingly to such rudimentary tactics. And we need to move swiftly to protect the crowds who sightsee, stroll and pose for selfies in the tourist heartland of London.

As attacks in Nice, Berlin and now London have demonstrated, cars and trucks are as potentially lethal as bombs and Kalashnikovs — but far easier to procure, and therefore presenting an incalculable risk to the people who congregate in the great cities of the world.

Westminster Bridge is the busiest tourist thoroughfare in Britain, connecting Parliament Square and Westminster Abbey with the London Eye and the other visitor attractions on the South Bank. At any hour during the day hundreds of visitors crowd the pavements and point their cameras, charmed by the miscellany of monuments in the centre of western Europe’s biggest city.

To mangle Wordsworth’s early 19th-century view of Westminster Bridge, Earth has much to show more fair than the awkward, if endearing, muddle where SE1 meets SW1. Yet in one sense we must turn the clock back to around 1802, a time without motorised transport. Buses, taxis and bikes, of course, must flow across the Thames. But we need to learn from Brussels, which suffered so badly exactly a year earlier.

The main thoroughfare that previously carved from north to south has been closed to normal traffic, and life at the core of the Belgian capital is returning to walking (or cycling) pace.

Barcelona, Copenhagen and every other great European city should also take note and begin to protect tourists and locals against mass murderers in secondhand saloons by accepting that heavy traffic and large crowds cannot mix.

“This is a day we planned for but hoped would never happen,” said Mark Rowley, assistant commissioner of the Metropolitan Police, as the toll of human suffering emerged.

With the greatest of respect to him and the brave men and women who serve with him, we must urgently plan for a city with humanity at its heart.