Your article on the negative effect that Ofsted can have on schools is a timely but wearisome reminder of its influence (“The Ofsted prophecy”, Cover story, 1 February).

A poor Ofsted inspection carried out by a good team can reveal that improvement is needed for pupils’ benefit, and rightly so. But a poor Ofsted inspection by a rogue team can spark a chain of events that spells disaster for the pupils.

Here in Lancashire, two schools were put into special measures in a two-week period. The inspections were characterised by an obsession with Department for Education data, a virtual refusal to look at school assessment, a lack of professional dialogue and detailed appeals that contained externally moderated support of the school but which were, of course, rejected.

Sir Michael Wilshaw makes the right noises but refuses to act when injustice occurs. This is just not good enough when his teams have the power to ruin careers.

Tony Roberts, Lancashire branch of the NAHT heads’ union.