Ian Woodhurst, the Campaign for the Protection fo Rural England's farming campaigner, said: "It's vital that bioenergy crops deliver the real carbon savings that they promise without damaging the character of our landscapes and our wildlife.

"With the right crop, in the right place, managed in the right way, we can provide our communities with the sustainable energy supplies they need to tackle climate change.

"But we need to make sure we don't end up with an agro-fuel industry that ends up wrecking the very thing we seek to protect."

Abi Bunker, agriculture policy officer at the Royal Society for the Protection of Birds, said: "This report should serve as a wake-up call to Government.

"Nearly 2.5 million acres could soon be planted with crops for biofuels and heat and power generation by 2020. That is a lot of land to sacrifice if environmental safeguards are not put in place first."

Sian Atkinson, conservation policy officer at the Woodland Trust, said: "Bioenergy offers some positive opportunities, not just for reduction of greenhouse gases, but also to improve biodiversity.

"For example, development of the wood fuel industry could stimulate markets for low-grade timber, enabling much-needed restoration of ancient woodland sites planted with conifers.

"However, there are also grave risks associated with the development of bioenergy, and we would urge the Government to address these concerns as a matter of urgency."