Matthew MacIver, chief executive and registrar of the GTC, tells me that these represent only a small proportion of the letters received. What nearly all of the letters, published and unpublished, have in common is a request by the writers that their names and addresses should not be disclosed. What does this reveal about the climate of Scottish education?

One interpretation is that the writers lack the courage of their convictions: they are content to write anonymously but are not prepared to take full responsibility for the views they express. In some individual cases this may be true, but the fact that there is a common pattern suggests another possibility.

Could it be that there exists in Scottish education a culture of fear, which makes teachers apprehensive about the consequences of speaking and writing in public about matters which are of professional concern to them? Some local authorities have policies about writing to the press which teachers, along with other employees, are required to observe.

Such constraints seem to me to exemplify a siege mentality on the part of councils but it is perhaps possible to justify a requirement that work addresses, such as schools, should not be used. Where home addresses are given, however, I cannot see any grounds for limiting the rights of teachers to voice their opinions in a democratic society. In fact, willingness to contribute to public debate should be welcomed as a sign of professional commitment.

I should make it clear that I certainly do not agree with the views expressed in all of the letters. Some of the writers advance arguments that I regard as defensive and conservative, and demonstrate a reluctance to change. But that is not the main point at issue here. What disturbs me is that members of a profession that is supposed to be concerned with the promotion of knowledge, understanding and critical thinking in others should be afraid to put their names to contributions to a journal read by fellow teachers. They must have some grounds for feeling that, if they put their heads above the parapet, they will find themselves subject to sanctions, whether formal or informal.

It is a sad indictment of the culture of Scottish teaching, and one that makes a mockery of official claims that the system is open, responsive and willing to listen. What it indicates is not only that the policy-makers have failed to win the hearts and minds of teachers, but also that they have created an atmosphere in which critics feel the need to cover their backs.

At conferences and other similar events, I have found that there is often a marked contrast between what is said in public and what teachers say in private conversation. Public contributions frequently invoke the approved policy discourse - with greater or lesser conviction - while private comments are likely to be much more sceptical. A form of professional hypocrisy develops in which honest statement becomes extremely difficult.

The result is that the intellectual currency of discussion is debased and trust in educational leaders is eroded.

It will not be easy to break through the pressures which lead to compliance and conformity, and which produce the fear that lies behind the anonymous letters. The process must start in initial training, where authentic student voices - as distinct from the rehearsal of establishment orthodoxies - should be welcomed. In the short term this may be an uncomfortable experience, but the long-term benefits could be considerable.

Walter Humes is professor of education at Aberdeen University.