"One is literally going in to say, `Does it work?' That's where I think inspectors, particularly senior inspectors, should be careful about making great judgements," says the inspector, who cannot be named because he has worked for Ofsted since leaving Her Majesty's Inspectorate of Schools in 1992.
He believes that standards have risen as a result of the National Curriculum and of the new inspection system.
"What business has 100 per cent success? But standards have certainly nudged up. In schools I have visited recently, there were things that could have been improved, but the children were reasonably served. It's been demoralising and difficult, but thinking about the National Curriculum has helped."
He adds that there have been far greater advances since his early years as an inspector. "Since the mid-1960s, things have dramatically improved. There is a better focus on what promotes learning, and more co-operation between teachers."
When he goes into a school, he says, he does not look at whether teachers are using the right methods, but simply at whether the methods they are using are appropriate to the children and to the subject matter they are teaching. Is their knowledge adequate, and are they projecting it in a way that gets through to the brightest and to the least able pupils?
"It's quite crazy to say one should never teach a whole class at once or to say that it should be all group work," he says. "The inspection criteria don't address whether it should be mixed ability or group work, whether there should be setting or streaming. It's irrelevant."
He believes schools have been forced to reassess their methods as a result of the national inspection programme, under which each one should receive a visit in the next four years.
"I think some form of national inspection is helpful, though whether it has helped as much as it could have is another matter."