Food companies were once a little blasé about the price they paid for the ingredients that went into their corn flakes, chocolate bars and yoghurts because in the 1980s and 1990s, prices of agricultural commodities were falling.

While many food companies took the precaution of hedging some of their key ingredients – Mars, the owner of Snickers bars, has been hedging cocoa since the 1960s – they did not have to worry too much about being caught out by unexpectedly big price jumps.