Damning verdict on GM crop

Final report on world's most comprehensive field trials says oil seed rape varieties would harm wildlife and environment

The following correction was printed in the Guardian's corrections and clarifications column, Thursday March 25 2005

Contrary to what we said in the report below, oil seed rape is not the largest single crop in Britain, neither is it the one from which farmers make most money. According to statistics published by the Department for Environment, Food and Rural Affairs, it comes third on both counts, behind wheat and barley.

The long-awaited final results of the GM trials for Britain's biggest crop, winter oil seed rape, show that wildlife and the environment would suffer if the crop was grown in the UK, in effect ending the biotech industry's hopes of introducing GM varieties in the foreseeable future.

The government, which has been keen to introduce GM crops, now has the results of the world's most comprehensive crop study, demonstrating that the GM varieties currently on offer would be detrimental to the countryside. Bayer CropScience, the company that owns the patent on the GM oil seed rape being tested, said afterwards that it was not going ahead with its application to grow the crop in Europe.

The Conservatives took advantage of the government's discomfort, with Tim Yeo, the environment spokesman, announcing that the party would not allow GM crops to be grown in Britain unless it could be proved they were safe for people and the environment.

The trials, whose results were published by the Royal Society yesterday, began before the last election when the public backlash against the government's plans to introduce GM crops stunned Downing Street.

Michael Meacher, the then environment minister, came up with a plan to get the government off the hook by running extensive trials of GM and non-GM crops to test their effects on bees, butterflies, bugs, weeds and other farmland wildlife in two farming regimes. Large fields were planted half with GM and half with conventional crops and the results compared.

It was widely predicted that the GM regime, which uses fewer applications of herbicide than conventional crops, would benefit wildlife, but for three out of the four crops tested the reverse was the case.

Yesterday's results were particularly significant because winter-grown oil seed rape occupies 330,000 hectares (815,000 acres) of British fields and is the largest single crop, and the one from which farmers make most money.

The main finding was that broadleaf weeds, such as chickweed, on which birds rely heavily for food, were far less numerous in GM fields than conventional fields. Some of the grass weeds were more numerous, although this had less direct benefit for wildlife and affected the quality of the crops.

The scientific results made it clear that it is not the GM crops that harm wildlife but the herbicide sprayed on them. Fields containing conventional crops are sprayed with a herbicide which usually kills weeds before the crops emerge but herbicide-tolerant GM crops can be sprayed later.

The results on this crop were that the patented glufosinate-ammonium weedkiller was so effective that there were one third fewer seeds for birds to eat at the end of the season than in a conventional crop. Two years later there were still 25% fewer seeds, even though the weedkiller had not been applied again.

Les Firbank, who was in charge of the trials, said: "These weeds are effectively the bottom of the food chain, so the seeds they produce are vital for farmland birds, which are already in decline. There were also fewer bees and butterflies in the GM crops. All the evidence is that it is the herbicide that makes the difference to the wildlife." Mark Avery, of the RSPB, said: "Six years ago, before the farm-scale trials, we were told that GM crops were good for wildlife and good for farmers' profits. Now, against all expectations, we are told they are bad for both. It is bad news for the biotech industry."

Elliot Morley, the environment minister, will await the advice of the government's advisory committee before making a final decision, but said the trials demonstrated the government's "precautionary approach on GM crops".

The European commission will today reluctantly give the go-ahead for other GM seeds and plants to be used commercially in Europe and demand that Austria, Luxembourg, France, Germany and Greece lift national bans.

Although aware that the decision will provoke a public backlash and be open to challenge, the 25 commissioners, according to documents seen by the Guardian, say they have no alternative but to "fulfil their legal obligations" and force through a decision because a regulatory committee of national scientific experts and then ministers could not reach a majority decision.

"We're caught in a trap. Though these are decisions bequeathed by the previous commission, we are expected to break the deadlock - and take the political flak," a senior official said.

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