UNDER THE MICROSCOPE: Mad cows and scientists

There IS nothing quite like the arrogance of ignorance. Sir Bernard Ingham, Lady Thatcher's former press secretary, is reported as saying that when the ridiculous BSE crisis is over the Government must bring our pathetic, destructive scientists under firm political control. This must rate as one of the most dangerous suggestions about the democratic process in recent times, and presumably reflects, for what else do press officers have to offer, the views of a significant number of Tory politicians.

The view that the scientists are partly to blame for the crisis that has destroyed the lives of many farmers, and has severe consequences for the economy, seems widespread. It is not hard to see why. For the conclusion that eating beef could be dangerous might, on a common-sense view, appear to be based on flimsy evidence. The key finding was the sudden appearance of a new form of Creutzfeldt-Jacob disease. But there are thus far just 12 cases. Is this enough on which to base the destruction of so many cattle?

The science of neither the cause of the disease, nor the way the infection shows itself over time, fit in with common sense. It is generally accepted that BSE came from cattle eating infected sheep. The infectious agent is thought to be a prion, which is quite unlike a virus or bacterium. But prions have difficulty crossing the species barrier, so what is the basis of the suggested danger that it could cause Creutzfeldt-Jakob disease in humans? The only explanation at present is that it's due to infection by a BSE agent.

While 12 cases may seem to be a very small number, why all the anxiety? This comes from an understanding of the pattern of infection of such a disease which has a long incubation time. The mathematical models of how many cases will appear over the next few years are complex, but could strike fear even into the heart of a press officer. There may be just a few more cases, but it is just as possible that there will be hundreds of thousands. No one knows.

BSE thus raises very difficult problems as to how such issues should be handled. One has to balance the risks against the cost of taking precautions. Our lives are full of such difficult choices. Fire regulations require enormously expensive constructions, though fires are rare. Building the Thames Barrier is a precaution for a very rare event. And some women at high risk choose to have a mastectomy to prevent cancer.

The social responsibility of scientists is to make public information that can affect our lives, not to make ethical or political decisions as to what to do. So I was shocked to hear the Minister of Health, Stephen Dorrel, when asked on the Today programme whether he would let his daughter eat beef, reply that it was not for him but for the scientists to decide. It is precisely such difficult decisions that politicians must take and, if they were less scientifically illiterate, they might be more competent to take them. A responsible government would share the relevant information with its European partners and inform and advise the public. It is also their moral and legal duty to take precautions. Muzzling the scientists will cut us all off from the only reliable source of information.

However complex the issues are, the only hope is to use science to understand them. Even if scientists are sometimes wrong and, on occasion, arrogant, at least they have something to be arrogant about. It would be most unwise to rely on the prejudices of the ignorant. ! Lewis Wolpert lectures at University College London