Drivers on Interstate 25 in Denver, Colorado, have to look twice to check the contents of the eight-storey glass tower by the road. But they are not mistaken. Inside, stacked high, are used cars that can be bought online and collected as if from a vending machine.

Customers of Carvana, the online used-car dealer behind the space-age structures, turn up and insert a token. Then, machinery in the building cranks into gear, shuffling the cars around and dropping the chosen vehicle in a lift, before the buyer buckles up and drives it off.

The slick technology is a far cry from the days when the industry had a reputation for Arthur Daley types flogging rusty old bangers at rip-off prices. During the pandemic, a wave