In 1973 Richard Nixon, US president, under political pressure be­cause of rising domestic food prices, banned the export of soyabeans. The policy had predictably dire results, but today, with the world in the grip of another bout of food price inf­lation, governments worldwide are rushing to distort the market with subsidies and quotas, price controls and export taxes. They should stop.

In the run-up to its presidential election, Russia has imposed price controls on basic foodstuffs, and plans an export tariff on wheat. China already controls prices; other importers, including Egypt, Jordan, Bangladesh and Morocco, are increasing subsidies or fiddling with their tariff regimes.