Tape measure

Regarding John Wakeford's suggestion that PhD students should tape their supervisions (THES, June 16), I have for many years been advising my students to do this. Not so that they could accumulate evidence against me, although they are, of course, free to do so if they wish, but because a good supervision sparks off new ideas from both supervisor and student, which need recollecting in tranquillity to test whether they are not only new but good.

I can thoroughly recommend the practice.

LEWIS ELTON

Professor of higher education

University College London