Pea growers are furious that Britain's supermarkets have cut the retail price of frozen peas just days after devastating flooding wiped out vast swathes of the crop.

They say they cannot understand Asda's move last week to cut a 0.9kg pack of own-label peas from £1.06 to £0.90 at a time when supplies are tight. Sainsbury's has also cut its price from £1.13 to £0.83 in the past fortnight.

NFU horticulture board chairman Richard Hirst said crop losses would be close to 40% and appealed to retailers to cut growers some slack. "The price cut will undermine the whole supply chain," he said. "It just shows the laws of supply and demand don't work any more."

There would be an exodus of growers next year after two poor harvests on the trot and rock-bottom retail prices, he warned. Processors and packers would also be hit by the downturn in volumes. "If prices rose 50p/kg, it would benefit everyone in the chain," he said.