I was appalled to read a defence of inadequate teaching by Professor Dylan Wiliam (“Bad teachers are not a big problem - but fire the stubborn non-improvers,” November 12).

“It’s not a big problem” - well, surely that depends on whether you are a professor of educational assessment, a demoralised colleague or a bored and defeated pupil.

“It’s a complex problem” - to say that we cannot distinguish reliably between good students badly taught and lower-achieving students taught well is disingenuous.

Professor Wiliam goes on to say that teachers who do not believe they can improve are much more dangerous than incompetent teachers. However, I would hazard a guess that these are not two separate groups, but one, and blaming “the kids” is this group’s default position.

Macia Grebot, Grebot Donnelly Associates, education PR and marketing, Twickenham.