Radical new plans to reduce traffic and limit our dependence on cars have sparked bitter conflict. As legal challenges escalate, will Britain’s great traffic experiment be shut down before we have time to see the benefits?

On an overcast Saturday afternoon in December, a convoy of 30 cars, led by a red Chevrolet pickup truck, set off from the car park of an east-London Asda with hazard lights flashing. The motorists, who formed a “festive motorcade”, wore Santa hats as they made their way slowly through the borough of Hackney before coming to a halt outside the town hall a couple of hours later.

They had gathered to register their outrage at being the victims, as they saw it, of a grand experiment that has been taking place on England’s roads since the start of the pandemic. As the national lockdown eased last summer, swathes of Hackney, stretching from Hoxton’s dense council estates at the borough’s western border with Islington to the edge of the River Lea marshland near Stratford in the east, had been closed to through traffic (with exceptions made for delivery vans, residents’ cars and emergency vehicles).