Consider the events of last week. First Royal Society scientists dismissed the work of Dr Arpad Pusztai with its claim that rats were grievously harmed when fed GM potatoes. Then the British Medical Association warned that such food and crops might have a cumulative and irreversible effect on the environment and the food chain. That was followed by the disclosure that the Government's Chief Scientific Adviser, Sir Robert May, agreed with those lobby groups which have demanded that the GM crops now being tested should not be approved for commercial use until at least 2003.
Next there was the first clear evidence that these crops pose a threat to wildlife: researchers at Cornell University had discovered that one of the world's most beautiful butterflies died when it came into contact with pollen from maize with a pest-resistant toxin engineered into it. Finally, on Friday, the Government issued its own review of the subject which declared that there was "no current evidence" that such technologies were "inherently harmful". It announced a "tough" new voluntary code on GM plantings. Critics, like the BMA, said that the moves were not robust enough, while countryside lobbyists said that previous voluntary codes have proved ineffectual.
Vested interests lurk behind so much here. The multinationals, even those with no interest in genetic modification, are determined to oppose calls that sovereign governments, rather than companies, should determine whether the import of GM foods and seeds be restricted. Such a shift would undermine the new freedoms they have acquired at the World Trade Organisation - thanks to international agreements which give free trade primacy over all other considerations. The Government relies on "independent" experts, many of whom gained their expertise in the pay - direct or indirect - of the same multinationals; it then adds to the impression of its partiality with secret meetings in which ministers try to spin the issue, even down to trying to fix which "independent" scientist appeared on the Today programme to support the Government line.
Ambiguities lie behind the claims and counterclaims. It is true that GM technology offers plants with new resistance to pests, so fewer chemicals will be needed. But in the case of GM soya, US farmers now use increased volumes of even more toxic chemicals than before, because the crop is resistant to them and everything else is not, boosting yields enormously. It is significant that the GM giant Monsanto earns half its $9bn income from just one such pesticide, Roundup. Its impact on the vast arable plains of America gives only a hint of the damage it would wreak in Britain's tiny fields and hedgerows.
In the Third World it is true that GM crops offer the possibility of feeding the starving; but they would probably also, like the hybrid seeds of the green revolution which wiped away famine in India in the 1970s, drive the poorest people off their land to make way for those who can afford the new technology. The shanty towns will mushroom.
The key question is: will the benefits outweigh the disadvantages? To answer that we need more information and less spin. That is why, today, we again urge the Government to declare a three-year moratorium on modified crops, and insist that all products containing modified organisms are clearly labelled. That is not hysteria. It is common sense. It is also good science.