The anxiety comes from an understanding of the pattern of development of such diseases which have so called long incubation times. Mathematical predictions of how many cases will appear over the next few years are complex but could strike fear even into the heart of a sceptic. No one knows. BSE thus raises very difficult problems as to how such issues should be handled. Because of the extreme dangers one has to balance the risks against all social and financial costs of taking precautions.
Government is about 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. 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. It is not for the scientists to decide, and it is precisely such difficult decisions that politicians must take. It is also their moral and legal duty to take precautions.