David Jackson, its director of research and school improvement, said shared values and beliefs about what the school stands for and where it is going were far more important.

“We all know development plans are a waste of time,” he told more than 100 Oxfordshire heads at a residential conference in Bournemouth. “By the time they are printed they are out of date.

“When you go to schools and ask teachers what’s in the development plan, they can never tell you. Every school has aims and they sound much the same.

“The head wrote them and even he or she can’t remember what they are. But what we can share is what we believe in.

“Leaders look beyond plans. The best schools have such a strong sense about where they are going that they look at external things and say, ‘that’s interesting but we wouldn’t do it like that, we would do it like this,’ or ‘we are not going to do it at all’.”

He cited the head of a successful school saying: “I can’t plan the ideas I’m going to have tomorrow.”

All schools are required to produce an action plan following an inspection by the Office for Standards in Education. Councils also have to produce one if a school is put into special measures. But development plans are not a legal requirement although they are common practice.