London

There are no human-health grounds for holding up the planting of transgenic crops in Britain, an expert panel has told the UK government.

But the panel said that the crops could have adverse environmental impacts, and should only be grown after case-by-case assessments of the risks. Its findings, released on 21 July, are expected to influence the government's decision on whether to license some transgenic crops for commercial planting later this year.

The panel was chaired by the government's chief scientific adviser, David King. Its work is part of a three-pronged assessment of transgenic crops by the UK government, which has also included a report issued on 11 July on the crops' economic impact, and a public consultation involving 500 meetings held around the country.

The process is being watched closely because British consumers' rejection of the technology is influencing its adoption in many other countries. “This will be influential internationally,” says plant scientist Mark Tester of the University of Cambridge.

But it remains unclear whether the panel's tentative green light for the technology will be enough to open the door to British cultivation of transgenic crops any time soon. Prime Minister Tony Blair has advocated the technology, but his unpopularity in the aftermath of the Iraq war may reduce the likelihood that he can persuade consumers, or environmental protesters, to accept it.

The panel, which included representatives from the biotechnology industry and conservation organizations as well as university scientists, struggled to reach a consensus, its members say. On the way, they digested more than 600 papers, lost a panel member, and survived a series of last-minute revisions that threatened to scupper the entire project.

“It's a minor miracle that the report got put together,” says panel member Mike Gasson, head of food-safety science at the Institute of Food Research in Norwich. Carlo Leifert, an expert in organic agriculture at the University of Newcastle-upon-Tyne, quit the panel last month.

The panel's report makes some concessions to critics of transgenic food, including, for example, the observation that allergens produced by transgenes may not be spotted during regulatory screening, and may only emerge once a crop is widely grown. But another fear often raised by environmental groups — that transgenic crops could give rise to herbicide-resistant 'superweeds' — was played down in the report.

Members were also split on whether extensive growth and consumption of such crops in the United States constitute evidence that they are safe to eat. The panel eventually agreed that the available research shows risks to human health to be “very low”.

A large-scale study of the impact of herbicide-tolerant transgenic crops on biodiversity, conducted by a team of UK-based scientists (see Nature 412, 760–763; 2001), is currently undergoing peer review, and the panel said it was reluctant to draw conclusions about environmental risks in the meantime. The panel said, however, that “the most important issue is [the crops'] potential effect on farmland and wildlife”, and pledged to update its report after the biodiversity study is published.

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