Consider this hypothetical scenario. A distinguished scientist - a world expert in his field - tests a technology used to produce 60 per cent of the food on his nation's shelves. To his amazement, it seems to damage his experimental animals' immune systems, brains, livers, kidneys and other vital organs - implying that the food could also endanger humans. Briefly, with the approval of his employers, he mentions this in public. All hell breaks loose. He is suspended from work and ostracised by his colleagues. His study is stopped. His computers are sealed, and the data from the experiments confiscated. The 18-strong team he had built up over 30 years is disbanded and he is forced into retirement. He suffers a heart attack.
The nation's government and scientific establishment mount a sustained assault on his reputation, accusing him of violating "every canon of scientific rectitude". His work is misrepresented: a minister says he has been "comprehensively discredited". He is gagged for seven months, unable to reply. And when one of the world's leading scientific journals decides to publish a short article based on the small amount of data he has been able to retain, it, too, comes under vociferous attack.
It is hard to think of any modern developed nation where such treatment would be countenanced. How different it would have been if the scientist had worked in a liberal democracy such as present-day Britain. Here, his reputation would have been respected, his work taken seriously. Teams of scientists would have done their own experiments to check it out, doubtless funded by a concerned government. If he were found to be right, urgent measures would be taken to safeguard public health; if he had got it wrong, his reputation might suffer, but that's all.
Well, the Kafkaesque nightmare happened in Britain, three years ago, to Dr Arpad Pusztai, who left Stalinist Hungary after the 1956 rising and came to Britain because of its reputation for tolerance. The author of 260 scientific papers and a self-confessed "very enthusiastic supporter" of genetic modification, he made his discovery by feeding GM and non-GM potatoes to different groups of rats, a study sponsored and approved by the government. What then happened to him is the starkest illustration that neither governments nor the scientific community really want to know the possible effects of GM crops on health and the environment. Pusztai wanted to do his research because he could find only one previously peer-reviewed study on feeding GM food to animals. Led by a scientist from the GM food giant Monsanto, it found no ill effects. Governments and the GM industry have a way of approving products that is specifically designed to avoid testing them. If GM crops are similar to non-GM ones in a restricted number of ways - such as in the amounts of fibre and fatty acids, protein and carbohydrates, vitamins and minerals they contain - it is assumed that chemical and genetic differences that do exist will not make them more toxic. Regulatory bodies pronounce them "substantially equivalent" to non-GM ones, and wave them through.
The significance of Pusztai's work was to suggest GM potatoes were toxic when non-GM ones were not - that they were not "substantially equivalent". If right, his findings could scarcely have more important implications. But the government did not rush to check it out: the old Ministry of Agriculture even told me that it would be "wrong" to try to replicate the research.
The attitude to testing the effects of GM crops on the environment is only a little less complacent. There are the "farm-scale trials" where, for the second year, scores of fields all over Britain have been split in half between GM and non-GM crops. Successive government statements have suggested the trials would provide conclusive evidence as to the safety of commercial development. But these trials are not even designed to look at the main question of concern: whether genes from the GM crops would contaminate other plants. They were set up to look purely at the effects on wildlife of different ways of using pesticides on the two crops. Some limited studies on "gene flow" have since been tacked on, but a new report shows they are too limited in both space and time to produce a conclusive verdict. The report - by the government's own Agriculture and Environment Technology Commission - concludes that the trials are not "sufficient" to provide a basis for deciding whether to grow commercial GM crops. Instead, as it points out, they were devised as a way to "buy some time" in the face of growing public opposition.
In 18 months, the time will have been spent, and we will still know little more. We do not know the answers, and are not going to find out. And if anyone does stumble across anything that raises disturbing questions, they would, scandalously, be well advised to keep quiet.
Geoffrey Lean is environment editor of the Independent