What he does not say, which considerably damages the case he is making, is that, ever since the introduction of the national curriculum, those teaching PGCE courses have been economical with the truth in licensing graduates to teach national curriculum science to 16-plus, irrespective of their qualifications.

Five PGCE days spent on learning some sub-GCSE physics does not prepare a biology graduate to teach KS3 physics let alone KS4. Many of the best physics graduates do not have a second science A-level, having taken double maths at A-level. Physics is also the least likely second or third science A-level to have been taken by most biology graduates. No wonder the recruitment of physics graduates is nose-diving.

This potentially catastrophic situation is a direct consequence of making science a national curriculum requirement rather than the separate sciences. What we now have is an increasingly specialist teaching force except in the sciences.

Headteachers do not expect historians to teach geography or geographers to teach history if they have no qualification in that second subject.

Yet they often have no such qualms in expecting biologists, chemists and physicists to teach subjects in which their expertise goes scarcely beyond the next page of the textbook.

Unless and until the separate sciences are again regarded on a par with other traditional subjects, the problem of recruiting not just good physicists but also biologists and chemists will not go away. Nor should it.

BRYAN R CHAPMAN

Moorfield Road Ilkley West Yorkshire