The QNCA will be charged with exercising quality control of assessment and qualifications, though there will be little satisfaction if the standard of the work assessed is declining. The purpose of examinations is not simply to sum up what has been learned during the course but to inspire candidates to raise their efforts.

While marginal candidates are turned off if the level of the challenge is too high, able candidates are quickly frustrated if there is little in the examination system to stretch them. The examination syllabus that suits one student may not suit another. Teachers who have become adept at teaching to one syllabus can be uncomfortable with another.

There is an argument that the syllabus should meet the needs of candidates if that can be done without lowering the overall challenge of the curriculum. One of the attractions of the general national vocational qualifications is that it allows students to thrive who would have found the approach of A-levels beyond them.

Does this mean that we need several examining boards and assessment authorities? England is unique in this. Scotland, Wales and Northern Ireland have single exam boards (even if some schools shop elsewhere). One advantage of the English system is that school departments that are unhappy with one board can take their custom to another. This may be done because a new and more exciting subject syllabus has been developed. On the other hand, it may be done because it is thought that the other board gives “better” results.

This psychology is not without its impact on the boards. There is little incentive to adopt a rigorous stance on maintaining standards associated with grades if schools then take their business elsewhere.

Reluctantly, many of my colleagues are coming to the conclusion that it is impossible to be sure that the standards applied in awarding a grade in a given subject in one board will be the same in another. Nor is it a simple matter of percentages. When I was chief examiner in A-level economics for the Oxford and Cambridge board, we consistently awarded more A grades than other boards. However, we had a high proportion of able candidates.

The only way to be sure that the standards applied throughout the country are consistent would be to have a single board. When I put that idea to a former exam board secretary, it was not greeted with enthusiasm. He asked me to imagine what it is like in a majority entry subject where the chief has several assistants and then to project those difficulties to the situation of a single board with perhaps five times the number of candidates and three or four tiers of examiners.

My colleagues are not always happy with the way the boards treat their school candidates but at least contact is usually at a personal level: the personalities involved are often known to each other. Minor problems can be resolved quickly. If there is to be a monolithic structure, attention would have to be given to achieving good links with schools.

No system of examining will be perfect and means must be found of quickly correcting the things that go wrong. I believe this could be easier with a single board which would not be concerned to protect its position vis-a-vis other boards. An effective method of appeals against results like the one in Scotland should be established.

The greatest worry would be loss of independence. Examinations, standards, league tables and many other aspects of education have become targets for politicians. We may share some of their concerns but there would be horror among my colleagues if we were to end up with syllabuses determined by party politics.

If the result of the Dearing proposals and the striving for control over standards is the emergence of a single examining authority, then we must at least ensure its independence and a good range of syllabuses so that there is sufficient scope for curriculum development.

Vivian Anthony is secretary of the Headmasters’ Conference.