The annual “clearing” scramble, in which students without university places are matched to the remaining vacancies, is often dismissed as a way of filling low-prestige courses with low-grade students. But the reality is much more upbeat.

In each of the past two years, law was the subject that took the most students through clearing — and the signs are that it will be the top recruiter again when the process starts today. Even the famously selective medical schools feature in clearing, although the 245 successful applicants via clearing last year all entered pre-clinical courses, extending the time taken to become a doctor.

So if your results are a disappointment, do not despair — almost one in ten of last year’s university entrants found their place in clearing, and in some popular areas the proportion was considerably higher.

In molecular biology, biophysics and biochemistry, for example — all of which demand high grades — more than 15 per cent of places were filled in clearing. Many of the successful applicants were aspiring doctors or dentists, whose four initial choices did not bear fruit, but low grades were far from the norm.

In general, students looking for a place in a subject with low entrance requirements can find one without clearing. They are in a buyer’s market as long as they have basic A levels, vocational qualifications or relevant work experience. Clearing is about those subjects in which the leading universities are oversubscribed.

More than 1,200 students (almost 10 per cent of last year’s intake) went through clearing to study psychology, for example — one of the most fashionable subjects of recent years.

Some small subjects that have too few students to qualify for the tables in this guide could hardly survive without their injection of post-results day talent. Metallurgy found a third of its students in clearing in 2005 and almost half last year.

Of course, the 1,600 law students who went through clearing last year did not go to Oxford or the London School of Economics. Most went to the new universities, whose profiles appear on pages 20-24.

But only a handful of universities will be entirely absent from this week’s lists on the website of the Universities and Colleges Admissions Service (www.ucas.com).

The numbers placed through clearing have been declining — there were 53,000 in 1997 (one in six of all degree entrants), compared with 38,000 (less than one in ten) last year.

But the 2006 total represented a small increase, as many universities struggled to fill their places. This summer, with applications back up to record levels, competition for places in popular subjects could be fierce.

Anthony McClaran, the Ucas chief executive, says: “The increase in capacity in universities has meant that more people get their first choices and clearing is not used quite as much, but it is still a very important part of the system. It is also done much more quickly now that so much takes place online, so students need to be prepared to act as soon as they can.”

Such is the speed of the modern process that most places that are going to be filled will be gone by the end of next week. Many will never be filled because supply outstrips demand in those subjects, but it is one of the curiosities of clearing that the vacancy lists never seem to get any smaller, although thousands of places have been taken.

Many courses remain listed in the vain hope of attracting one last outstanding applicant, when they are effectively closed to others. Applicants need a clear and realistic idea — preferably even before they receive their results — of their likely targets in clearing. Many universities now publish provisional clearing lists on their websites well before A-level results day.

Although no one wants to be too pessimistic before learning their grades, many of those who drop grades will have a strong suspicion that clearing beckons. A little advance preparation will go a long way.

The biggest danger in clearing is rushing into a course or institution that turns out not to be as expected. Research has suggested a higher drop-out rate among those who enter through clearing, often because the student has opted for a different subject to his or her first choice and at a hastily-chosen university. Speed is important in clearing, but the normal rules of decision-making still apply.

Times recommends

• Students face big rise in university fees
• Students to rate lecturers online
• Lord heads team to look at raising tuition fees