The same disregard for subject specialism is also true for history, RE and several other subjects. Trainee teachers on secondary courses are thoroughly assessed for their subject competence.
The utter nonsense, however, is that from their day of qualification, a teacher can be asked to teach almost anything. Whether this makes a nonsense of the training process, or of what headteachers are free to do in schools, is quite another matter. I do, incidentally, fully accept that with specialist support, many non-specialists teach first-rate lessons in subjects for which they have no formal qualification, up to a point.
FRED MARTIN. PGCE tutor in geography with IT. Bath Spa University College. Newton St Loe, Bath