Billions of miles have been driven on Britain’s roads this decade in cars fitted with “telematics” boxes recording every detail of a driver’s behaviour – whether they are speeding on a 30mph urban road, how they are cornering on a country road, and how they are braking or accelerating on a motorway.

Installed in about 1m cars by insurance companies, they offer drivers – usually 17 to 25-year-olds – less costly insurance if they drive more carefully. But the telematics black boxes also reveal a wealth of data about how Britain drives - debunking a lot of modern myths, but confirming many others.