Prices for quality spring wheat have soared 90% in the past six weeks.

On Friday, prices for wheat used in bread rose to an all-time high of $19.88 (£10.16) a bushel - the highest yet paid for any wheat contract and a three-fold increase from a year ago - according to the Financial Times.

It comes as The Grocer revealed this week that the price of durum wheat had rocketed by two and a half times since last June because of tightening supplies.