I have been more conscious this year than in earlier years of some of the difficulties of the admissions system for school-leavers, but I have not become any clearer about the best way forward.

Several anguished letters from parents whose children have done much better than their schools expected have complained that there is no post-A level way into very favoured subjects, such as medicine, without waiting a year. While that is not absolutely accurate - a few students do always get into medicine in August - there is much truth in this perception.

But does this matter? More and more students take a "gap" year between school and university, and this trend may well accelerate as financial pressures grow. Against this, it can be argued that it is able students from families of limited means who may least wish to take a year out at this stage, and that this group may be disproportionately represented among the "underpredicted".

Then there is the much larger group of school-leavers who have come to understand, correctly, that the so-called contract between a university and an applicant contained in a conditional offer is a wholly one-way affair. Students who fail to get into their first-choice institution often no longer feel bound to go to their reserve choice, and students who do better than expected feel no obligation to go to their hitherto first-choice institution. Students can and do change their part of the contract unilaterally if it seems advantageous to do so, and can one really blame them?

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These problems are compounded by the fact that predicted grades, on which the present system is based, can be inaccurate and are certainly uneven. This leads to perceived inequity in the way candidates from different schools are treated, and is particularly irritating to headteachers.

But the arguments for a post-A level system are not without their difficulties. There is certainly no political will to fund large numbers of young people to permit a January start to the academic year, so a September start must stay. That means that a wholly post-A level system would put quite intolerable strain on university staff.

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To enable all school-leavers to visit one or several universities in August, consider courses and accommodation and to make reasoned decisions would require so many staff to be present at the only time when leave is currently possible as to be entirely impracticable.

But why not allow the visits and discussions to take place in the spring, as now, with only applications and (immediate) decisions made in August? I see two problems with this. First, one of the objections of schools to the present system - the expense and disruption of visits during the A-level terms - is not addressed. Just as important, there will be absolutely no way in practice of preventing students, particularly the ablest students, reaching agreements, whether formal or informal, with their favoured institution: in effect, obtaining a pre-A-level offer, conditional or otherwise. Perhaps this does not matter, but it does mean that a wholly post-A level system is simply not going to materialise in a world where the student consumer is all-powerful.

So the real choice is between the present system with its acknowledged flaws and some form of mixed system, as the university/ schools working party is proposing. What intrigues me is whether a mixed system can guarantee at least a few post-A-level places in all subjects in all institutions. If it does not, it will not help me to reply to next year's anguished letters.

Martin Harris is vice chancellor, University of Manchester.

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