Richard Cairns might well be correct in asserting that A-level grades provide a more reliable yardstick of teaching potential than the degree-class someone achieves, given the differences in quality among various courses and institutions (“A-levels, not degrees, are what count in teacher recruitment, says top head”, 11 February).

However, I am left pondering whether Mr Cairns would reject an application from Professor Brian Cox on the strength of his D-grade in A-level mathematics, an admission made on the BBC’s Breakfast show, broadcast on 2 February. Of course, this assumes that Professor Cox would want to relinquish his chair at Manchester University and escape the limelight of presenting TV programmes such as the BBC’s Wonders of the Solar System in favour of Brighton College.

Perhaps assessing teachers against a mix of criteria is the fairest approach - one that is already followed by Brighton College, I suspect.

Dr Mike Follows, Willenhall, West Midlands.