Green campaigners have called on the government to ensure that fuel made from energy crops meets minimum environmental standards.

A misjudged push for biofuels could actually contribute to global warming rather than helping to tackle it, claims a joint statement by four environmental groups.

The statement – issued by the RSPB, WWF, Greenpeace and Friends of the Earth – acknowledges that biofuels could play an important role combating climate change.

But it claims that the government’s Renewable Transport Fuel Obligation (RTFO) is ill thought out and lacks appropriate safeguards.

The RTFO requires transport fuel suppliers to ensure that 5% of all UK road vehicle fuel is supplied is from sustainable renewable sources by 2010.

But the green groups want the obligation tightened so biofuel producers must meet minimum greenhouse gas and sustainability standards.

In its current form, they claim businesses could produce biofuels by destroying rainforests, actually releasing more carbon into the atmosphere than is saved.

Greenpeace chief scientist Douglas Parr said: “The government must sort out this botched plan or risk losing the value that biofuels can offer.”

Environmental audits should be introduced to cover the whole life-cycle of the fuels, from growing the crop to transporting it to the pump, said Dr Parr.

Without strong, mandatory standards, increasing amounts of biofuel would be produced at the expense of rainforests, peat lands and natural grasslands.

Those standards should include a requirement that biofuels achieve a 50% saving on greenhouse gases compared to fossil fuels.

They should also take account of the greenhouse gases released by land-use change and forest clearance.