So, Ofsted plans dawn raids to monitor behaviour in schools, but only on those already deemed to have “problems” (15 July).

I recall leaving a governors’ meeting at the end of a full-on Ofsted inspection week a couple of years before I took early retirement. I spoke to the then chairman who was delighted that the debriefing had revealed that Ofsted judged our school “satisfactory” (in the days when it meant exactly that). I pointed out that it wasn’t really a sound judgment as the entire staff had been on emergency full throttle for about a month, driven by a panic-stricken head and that the week itself was a completely artificial interlude in the life of an otherwise, well, “satisfactory” comprehensive school.

Unannounced inspections will certainly produce far more accurate judgments about a school, even if they might introduce new difficulties.

The vexed question of behaviour in a school will never be properly addressed as long as it is possible for heads to duck the issue.

There are many “stories” about how heads prevent Ofsted inspectors from bumping into their worst-behaved pupils - and they are dismissed as apocryphal by those who prefer not to believe them. I was actually involved in one example of deceiving Ofsted while working as a supply teacher.

I was given my timetable for each day but from the first day the strategy was clear: I was sent to lessons that had their usual teacher in attendance. The inspectors were handed the supply-cover timetables each day, so were unlikely to visit those classes. The classes I was sent to over the course of the inspection were all very difficult ones. The politically correct description would be “challenging”. The truth was that they all had more than their fair share of very badly behaved pupils. The gamble paid off: none of the classes I “covered” were visited.

Maybe if Ofsted’s raiding inspectors found more examples of teachers having to cope with undisciplined children, then the real extent of the problem - which dissuades some graduates from entering the profession, persuades many new entrants to leave quickly and drives many older teachers to retire early - might be recognised, though I doubt it.

Tom Trust, Redruth, Cornwall.