Remember the old N grade at A-level, the “near miss” quietly buried with the introduction of new AS and A-levels three years ago? Remember John Patten’s proposals for an A* at A-level and Labour’s “A grade with Distinction”, which was put on hold pending attempts to breathe new life into Advanced Extension Awards, marketed by the spin doctors as world-class tests?

This year’s A-level results have re-ignited the debate about how to distinguish between the brightest pupils and how to cope with an ever-rising pass rate. With the overall pass rate reaching a new high of 95.4 per cent, there just isn’t room for a grade between E and fail. Yet, at the top end, where more than 20 per cent of grades awarded nationally are As (the figure is double that in the independent sector), the system is crying out for some means of discriminating “the best” from “the rest”.

Few people, even within the Qualifications and Curriculum Authority itself, really believe that Advanced Extension Awards (AEAs) are the answer. With only a very modest increase in take-up of AEAs this year (5.6 per cent) and a continuing failure rate above 50 per cent, these costly, demotivating, exclusive and time-consuming exams are unsustainable in the long term. But if AEAs are not the answer, what is?

In the absence of a tool to help them differentiate between equally well-qualified individuals, universities (and employers) are looking beyond A-level for help. American-style SATs, tests of aptitude and potential such as Cambridge university’s Biomedical Admissions Test (BMAT), psychometric tests and the like are mushrooming. Even the Government appears to be looking outside A-level with Mike Tomlinson’s proposals for an extended research project and essay to stretch students as part of a new English baccalaureate.

But this is years away. In the meantime, a solution is needed which meets the following criteria. It should be easy to understand, require little or no extra examining time or special teaching, be part of the A-level, not a bolt-on extra, and be a national solution.

There appear to be five main options which would meet these criteria.

* Extension papers: a higher tier at A-level, “A3” alongside AS (A1) and A2. Unlike AEAs, these would be available in all subjects, and questions would be based on the normal A-level syllabus. The disadvantage is that they would require extra examining time, possibly extra teaching and prior selection of students.

* Extension questions: instead of separate papers, there would be more challenging questions as part of the A2 synoptic papers (taken at the same sitting). In some subjects it would be possible to give credit for more extended or original answers to normal A2 questions. More time would, however, still need to be added to the A2 papers but these would be open to all candidates.

* Reporting achievement in terms of overall marks (possibly as a simple percentage alongside grades): an option Cambridge university appears to be considering. Candidates’ scores would be made public. For this to be effective, applications and admission to university would need to take place after the results were known since it is the A2 scores which top universities really want to see. The key danger is that this might fuel the re-sit culture and divert students into yet more depth at the expense of breadth.

* Recalibrating the A-level scale: the present five grades (A-E) would be replaced by six, giving higher achievement a new grade, with no pre-set limit on the proportion achieving it. If one wanted to avoid calling the top grade “A*”, the scale could be recalibrated 1-6, with 1 as the new “super-grade”. Accusations of devaluation would be hard to rebut, at least until the new “currency” became accepted.

* Norm-referencing the top grade: the new grade (A* or 1) could be awarded to the top 5 per cent nationally achieving grade A in each subject. It could be as elitist (top 1 per cent?) or inclusive (top 20 per cent?) as one wanted it to be. This would be relatively easy to introduce, involve no additional exams for students or markers, and would be readily understood by the public.

Until now, the Headmasters’ and Headmistresses’ Conference has resisted anything resembling an A* at A-level. The objections remain: it could devalue the existing A grade, it could escalate re-sitting, it could distract students from other worthwhile (non-examined) activities. But the context for debate has changed. If no solution to the problem of discrimination at the top is found (and soon), the A-level itself and any concept of national standards will be replaced by anarchy and incoherence as universities and employers go their own way. It is time, at least, to re-open the debate on the A* at A-level.

Geoff Lucas is secretary of the Headmasters’ and Headmistresses’ Conference