Robin Twizell, managing director of Renewable Energy from Agriculture, which encourages farmers to provide industry with energy crops, said the landscape would not be turned over excessively to them because the amount grown was dictated by global prices and the need to rotate crops to protect the soil.

Mr Twizell said: "You have to rotate crops because if you don't, they keel over, and if they keel over, there is no yield, and if there is no yield there is no money.

"If you grow too much, the price collapses and supply outstrips demand."

He said farmers were also acutely aware of their need to protect wildlife.

Mr Twizell said: "Most farmers are environmentalists. They are not short-termists. They know that if they go out and rape the countryside, there will be trouble in the years to come. They recognise the need for conservation even if that means a little less income now."

He said farmers growing energy crops already encourage wildlife through measures such as leaving corridors along which creatures can travel and that the endangered bumblebee actually benefited from oilseed rape.

Describing the environmentalists' report as 'a little too simplistic,' he did nevertheless support the call for the Government to do more to help farmers protect the land. "It does need a more thought-out approach," he said.