These, remember, are the same students who a year ago were creating merry hell about the pressures of the AS exams. They are not an unusually clever cohort and did not come through the school with a particularly hardworking reputation, but they are undoubtedly focused now.

Presumably, they have benefited from that extraordinary and awful lower-sixth year. Maybe the chemistry of the huge work demands and anxiety of not knowing what the examiners were expecting, along with the relief of the actual exams proving less difficult than they feared - and their excellent grades - have made them mature and responsible before their time.

Certainly a powerful force has been unleashed, and we would be wise to recognise its impetus and build on it. For too long the lower-sixth year was accepted as a transition period between the demands of GCSE and A-level, a myth that generations of first-year A-level students were only too willing to live up to as they played cards in so-called private study lessons and partied the nights away in preference to homework.

Last year, the pressure imposed by anxious teachers caused the pendulum to swing too far the other way; academic demands meant that sport, music, drama, debating, prefect duties and work-shadowing all fell by the wayside. The priority now is to make sure that future students focus as well as this upper-sixth group has done.

You could argue that last year’s AS-level experience is unrepeatable (true of the comments the students made at the time), but we would be foolish not to learn the lessons that emerged - albeit accidentally. The difference in the students’ approach was caused by additional teaching contact time - and consequently fewer free periods to divert their concentration - and the incentive of the impending exams.

As upper-sixth students, in most cases now with less contact time, the focus is already established. This experience demonstrates that there is no sense in turning back to what the A-level curriculum used to be like. We need to recognise that the ASA2 structure offers a flexibility that did not exist before. If we are to continue to prize A-level above the alternative baccalaureate-style approach, this is the nearest we are ever going to get to a system that combines the advantages of both.

As the post-16 institutions move forward with the system - and develop its effectiveness - we need help from the Government and the universities, preferably from both working together. It must be possible for the universities to co-operate to create a more straightforward and transparent system of applications and offers. Why, for example, is the nonsense of whether general studies is, or isn’t, an acceptable A-level allowed to continue? As things stand, it completely wrecks the validity of any comparative A-level statistics. Some universities accept it, some don’t; some courses in the same university treat it differently. In my view, it is as intellectually demanding as other A-levels - and is one subject that has benefited from the syllabus development of the past two years. Another is the randomness and frequency of university open days and interviews, which play havoc with the coherence of A2 teaching.

The structure of the A-level years is at the heart of what remains to be done. In the long run, a more measured transition for students from the A2 course into universities should replace the present free-for-all - which we accept as if there were no possibility of it being done differently. In the meantime, all AS exams should be completed by half-term in the summer, because refreshed students could then put in serious foundation work for A2s, get to grips with research studies and do some of those broadening activities that are otherwise squeezed out of the curriculum.

John Claydon is head of Wyedean school, Chepstow, Gloucestershire