But imagine yourself interviewing 40 candidates for eight places. Then answer the following questions:

- One candidate shakes you firmly by the hand, looks you in the eye, appears interested in what you say and is keen to make a contribution. Another offers you a flabby handshake, avoids your eye, answers in monosyllables and makes no independent contribution. To which candidate would you be more drawn?

- Asked which news items interest them, one candidate replies “I don’t follow the news”, the other talks animatedly about a current issue and its relevance to their proposed course. Both candidates have applied and read politics, philosophy and economics. Which candidate would impress you more?

- One candidate, pressed on the inconsistency between two claims, reacts defensively, continues to assert both and loses his train of thought. Another acknowledges the inconsistency and considers which claim to drop, reflecting (aloud) on her reasons for and against each. Which candidate would strike you as the better thinker?

The obvious answers to these questions indicate part of the reason for the success of the independent sector in Oxford entrance. Pupils from this sector, in my experience, exhibit a social competence, an interest in current affairs, and a willingness to criticise themselves and be criticised by others that is often missing in pupils from maintained schools. Were more maintained schools to start effectively promoting social skills, debate about current affairs, and critical thinking, pupils from the independent sector would lose much of their head start.

It is, of course, part of the interviewer’s job to discern the intellect beneath the surface. Someone who has never tried thinking critically might turn out, given a chance, to be good at it. But interviewers are only human. Social competence, a lively interest in one’s surroundings, and a willingness to question one’s beliefs easily masquerade as intelligence. I have no doubt that we often get it wrong. It is a shame - to say the least - that the lack of these skills disadvantages candidates from the maintained sector, especially when they can be taught.

It might be objected that pupils from maintained schools will be more nervous than their independent counterparts and that it is this, rather than lack of these skills, that hampers them. But all candidates are nervous. If independent pupils are less nervous this too, I suggest, is the result of the actions of independent schools, rather than any bias in the system.

First, independent school teachers are often familiar with Oxford, and prepared to impress on pupils the possibility, in principle, of their getting in. This is not always the result of some old boygirl network: any teacher who wants to develop contacts in Oxford has only to attend one of the regular meetings that Oxford colleges hold for schools.

At these meetings the colleges explain procedures, demystify systems and encourage socialising. Many disciplines hold similar meetings for subject teachers. To find out about such gatherings one only has to ring college admissions secretaries, (or the admissions office of the university itself). Independent schools make more use of these opportunities than maintained schools.

Second, independent school pupils will often have met their interviewers.This enables them to see that their interviewers are human, and gives them confidence in their approach to the interview. These meetings often take place on an open day, or as the result of a phone call made to a tutor from a teacher or head who has nurtured the sort of contacts mentioned above.

I am not the only person who is always happy to be rung by a school and asked if I will see a particular pupilgive a talkplay host to a group, or answer queries. It is the job of the admissions tutor (and every college has one) to do such things. Again, independent schools make good use of such opportunities.

Third, possession of the skills outlined above engenders the confidence that enables one to cope even when one is nervous. Social competence, for example, generates the belief that others will be as interested in you as you are in them.

An interest in current affairs promotes a confidence-building sense of being an integral part of society. And the ability to think critically brings the security of knowing that, with effort, one can understand what is being said and make an appropriate response.

I have interviewed for Oxford entrance for 11 years. I went to a maintained school myself, as did many of my colleagues. I have never come across prejudice against such schools. I believe that if maintained schools were to promote the skills outlined above, and make use of the networking opportunities Oxford offers, independent school pupils would have far less of an advantage than they do at the moment.

Marianne Talbot is a philosophy tutor at Brasenose College, Oxford, and is a consultant for the Qualifications and Curriculum Authority working on the promotion of pupils’ spiritual, moral, social and cultural development