G20 countries are to step in to try and co-ordinate a response to surging food prices, after the worst US drought in half a century devastated crops in the world’s largest agricultural exporter.

A rotting ear of corn sits on a struggling corn plant in a drought-stricken farm field.

The conversations behind closed doors among senior G20 and UN agriculture officials about calling a session of a new emergency forum come after the cost of corn, or maize, surged to an all-time high, surpassing the level seen during the 2007-08 food crisis.