After our Office for Standards in Education inspection, I mentioned to the lead inspector that one of our heads of department felt that the inspector of his subject was not fully au fait with the syllabuses. I was asked which examinations board the teacher used. Then I was assured that everything must be all right, since the inspector in question examined for that very board.

Think about it: your OFSTED inspector in the spring can be your examiner in the summer (and, if you appeal, your adversary in the autumn). The same person can have total access to coursework and other preparatory material during the inspection and knowledge of examinations questions and marking policy at the same time.

Moreover, that person will also be responsible for personal debriefings and may volunteer well-intentioned advice as well. I impugn no individual’s integrity here - it’s the principle that matters. I thought - and think - that it’s wrong.

I wrote to Her Majesty’s Chief Inspector of Schools, Chris Woodhead, to see whether he agreed. Quoting the relevant section of the Schools Inspection Act 1996, he replied: “It is the duty of the registered inspector ... to ensure that no member of the team has, or has at any time had, a connection with the school which might reasonably be taken to raise doubts about their impartiality in relation to the school. In this case, the registered inspector clearly decided that no such connection existed.”

OFSTED has such a foul reputation that anyone defending it risks dead cats through the mail for a month, but I still say that an evidence-based independent national inspection service is the best protection teachers have against arbitrariness and faddishness. So, long live OFSTED. But, if it is to secure the respect of the profession, it has to get rid of its warts.

First, as we all know, OFSTED must publicise teachers’ achievements as well as their shortcomings. When, as with our inspection, a team describes itself as “OFSTED with a human face”, you know that it isn’t just teachers who have a problem with inspections - it’s OFSTED, too.

Then there is this “reign of terror” business. I say, if you can answer to yourself, you can answer to anyone, but that doesn’t help when grown men and women tell you: “If I don’t see it, it doesn’t exist.” What nonsense to expect to see everything in three or four days! Yet it’s enough to skewer conscientious teachers very painfully.

Conscientious teachers also know that, try as they might, they simply can’t do everything required of them, so they let some things slide in order to concentrate on essentials. Then an inspection is announced, and what by any other standard is sound professional judgment suddenly becomes reportable professional inadequacy. No wonder some teachers panic before an inspection. They do their best and then are made to feel like goats.

And now we get this profoundly serious blurring of inspectors and examiners made possible by legislation which is weak and murky where it ought to be strong and clear. Obviously, there should be an absolute fire wall between the two functions, and OFSTED will be sullied for as long as there isn’t one.

However, don’t blame Mr Woodhead for this - he had no power to intervene. The legislation must, clearly, go back to our legislators.

Colin Butler is senior English master at Borden Grammar School, Sittingbourne, Kent