What they care about are top grades and a passion for the subject. The applicant’s brain is what is important, not whether they can exude public-school confidence.

But many state schools remain unconvinced. Growing numbers are turning to specialised Oxbridge coaching courses. One consultant runs etiquette classes to teach the basics of behaviour at interview.

Rachel Holland has taken her “charm school” to five state schools, showing the children of blue-collar workers how to carry themselves in the halls of academe. Pupils are taken through the intricacies of handshakes, eye contact, dress and even how to sit. “It helps the applicant to feel comfortable and confident so they will be better able to put their point across,” she says.

She uses clips from the film Pretty Woman - where a prostitute accompanies a rich businessman to various events - to illustrate how to behave in unfamiliar situations.

Ann Holland, headteacher of Cotswold School in Bourton-on-the-Water in Gloucestershire, believes it is important to give hert pupils the poise and confidence of any fee-paying pupil at interview.

“This training won’t improve their intelligence or exam results but it gives them that confidence,” she said. “It’s easy for the admissions tutors to say that none of this matters but they are influenced on a subconscious level. They are receiving subliminal messages and this extra training gives our pupils a more level playing field.

“In their interviews pupils will perform better if they feel their ideas are worth listening to.”

Rachel Holland leaves preparations for the content of interviews to schools or other all-round consultants, such as Oxbridge Applications. The latter is now involved with 200 state and 200 private schools and claims a 46 per cent success rate for applicants, compared to the 24 per cent national average. Local authorities have been criticised for using money from the Aimhigher access to higher education programme to buy in such services.

In Brent, where ethnic-minority residents outnumber whites, Oxbridge Applications is used to ensure consistency for candidates across its schools.

Peter Boursnell, the Aimhigher co-ordinator in the north-west London,borough, said: “Oxford and Cambridge finance good work to widen participation but I believe there’s a lot more that can be done.”

A recent report from the Sutton Trust education charity showed a third of Oxbridge admissions came from just 100 schools and colleges, 80 per cent of which were private.

And Alan Ryan, the warden of New College, Oxford, recently told The TES he thought admissions procedures were “socially biased” against state school pupils.

However, the universities are at pains to insist that the advice they offer is more than enough to help pupils prepare. Geoff Parks, director of admissions at Cambridge, said that coaching in manners and communication might only be useful for a subject where these skills were vital, such as medicine.

“Otherwise, we are much more interested in the quality of the answers rather the style in which they are delivered,” he said. “I don’t know why the idea persists that presentation is so important.”

Dr Parks emphasised there were other reasons for the higher acceptance rate from independent schools. Pupils from grammar and fee-paying schools had often been better advised on suitable subject combinations at A-level, he said.

Schools with more experience in sending students to Oxbridge also had a better understanding of the standards and tended not to make “unrealistic applications”.

Degree subject choice was also an issue, with more applications for less competitive courses, such as Latin, archaeology and anthropology, coming from independent schools.

Roger Pope, of Kingsbridge Community College in Devon, is one of many heads who sees private coaching as unnecessary. About two of his pupils a year are accepted to Oxbridge. His school offers mocks interviews to those who want them.

He says that if pupils want to apply, the school would try to find experts in their subjects or past graduates to advise them. But he feels that private coaching offered students an unfair advantage.

“I can understand why people go for this but I find the whole notion horrific,” he says. “They are trying to put on a bit of final polish when it should be about the process of their 13 years of education.

WHO GETS IN:

OXFORD

25%: of state school applicants 1,437 out of 5620;

33% of fee-paying applicants 1,212 out of 3,625;

54% of undergraduates are from state schools. Target for 2011: 62%.

Budget to achieve that: pound;3m.

CAMBRIDGE

24% of state school applicants 1,527 out of 6,387;

34% of fee-paying applicants 1,214 out of 3,520;

57% of undergraduates are from state schools.

Target for 2011: 60-63%.

Budget to achieve that: pound;3m.

Source: Oxford and Cambridge universities 2006.