Germany does it, France does it, the US is edging towards doing it – and Britain is under pressure to follow. State-run, car-scrapping incentive schemes seem to work. German consumers receive €2,500 towards a new car if they scrap one above nine years old: car sales there rose 21 per cent year on year last month. In France, which offers only €1,000-€2,000 scrapping subsidies, sales still fell 13 per cent but less than the 22 per cent drop seen in the UK or the 49 per cent in Spain. Such schemes have helped prompt Renault to start building more small Clios at a French plant (not, despite initial confusion, at the expense of a Slovenian factory).

These incentives can do what chucking money at manufacturers cannot: persuade consumers to spend. They claim environmental benefits, too, since consumers generally buy small, lower-emission cars. But they are double-edged. Incentives pull forward demand, creating a nasty fall-off when incentives end. And eco benefits must be weighed against the impact of building new cars while crushing still-viable old vehicles. They also, potentially, distort competition. The US dumped a “cash for clunkers” plan last year amid grouching it would help importers. A new bill last week has a protectionist whiff, restricting a proposed incentive to cars assembled in North America.