Even experienced teachers have been asking themselves how they can teach A-level subjects when they don’t know the standard on which half the course will be examined. Perhaps ministers are wondering how they can have a standards agenda when nobody knows what the standards are.

The issue of A-level standards is at the heart of teaching. I cannot recall a bigger crisis in my 35-year career in education. To tackle it, five separate issues need to be addressed.

First, justice must be done for the 2002 candidates. It is a sad irony that the “guinea-pig generation” of 2002 18-year-olds - who produced record results, despite being victims of so many education reforms - should be the ones to suffer.

Second, public confidence in A-level standards must be restored. The second part of Mike Tomlinson’s inquiry will have to look beyond this year’s debacle to the problems at the core of A-level.

It is not just a question of the standard at which A2 should be marked so that this balances easier AS modules. More fundamentally, there is no single A-level standard.

The thousands of schools using Professor Carol Fitz-Gibbon’s A-level information systems have known for years that the so-called gold standard is a myth. Some subjects are harder than others and always have been. The fact that the Tomlinson report stated that no one breached the code of practice is a reflection of the inadequacy of the code, not a justification for what happened.

Third, a new relationship must be found between the Government, the Qualifications and Curriculum Authority and exam boards. The departure of Sir William Stubbs provides the opportunity for the QCA to forge a new relationship with its stakeholders. I have always believed that the QCA should be independent of the government and directly responsible to parliament. It is right for governments to establish the framework of curriculum and examinations, but the detail of the curriculum and the regulation of the exams system should not be under political control. Recent events may make ministers more inclined to agree with this view. There have been periods when curriculum and assessment were the responsibility of separate bodies, but this did not work. Curriculum and exams should remain with a single body. However, the QCA should no longer set national curriculum tests and its role as independent regulator needs to be clearer.

Pressure for a single exam board will grow, but the number of boards should only be reduced if the external examinations industry is slimmed down to more reasonable proportions. This leads to the fourth point, the need for a major review of assessment and examinations.

Young people are subjected to far too many external exams and the purpose of each has become confused. The results of high-stakes tests now inform students and parents, university admissions tutors, school league tables, national targets and performance pay for teachers. Examinations have become the master of the system, instead of the servant. Greater trust needs to be placed in the professionalism of teachers and more of the assessment at A-level, particularly AS, should be internal. The country now understands that examining is not an exact science and greater reliance on teacher assessment, supported by fewer external tests, would make the system more reliable.

Finally, planning must start for a successor to A-level, which celebrated its 51st birthday this year. We need a broader post-16 curriculum, clearly linked to GCSE and lifelong learning. Vocational education must find a stronger place. A bold reform of 14 to 19 qualifications could be Estelle Morris’s legacy, remembered long after we have forgotten about this crisis. An English baccalaureate could be the answer, but that is for another day. A-level is here to stay for a few years yet and we must not be deflected from solving the urgent problems identified by the Tomlinson report.

See 16-page pull-out on assessment John Dunford is general secretary of the Secondary Heads Association