The government wants more students to apply to top universities

The Sutton Trust found 45% of private pupils with an A and two Bs or better at A-level went to one of the UK's 13 highest-ranked universities.

However, for equivalent state-educated teenagers the figure was 26%.

The trust's founder, Sir Peter Lampl, said universities were acting in independent schools' "favour".

'Waste of talent'

The figures equated to 3,000 state pupils missing out on their "fair share" of the 30,000 places at the leading universities.

Based on surveys by The Times, Daily Telegraph, Sunday Times and Financial Times in 2000, these were: Cambridge, Imperial, Oxford, London School of Economics, University College London, York, Warwick, Bristol, Nottingham, St Andrews, Birmingham, Edinburgh and Durham.

The trust found that state pupils with an A and two Bs or better at A-level were more likely than those from independent schools to go to universities which were polytechnics before the system was unified in 1992.

Sir Peter said: "There has been a lot of political debate about the issue of university access, and lots of accusations have been made by those who see greater access as being possible only through positive discrimination.

"Our report gives the facts. Around 3,000 able state school students make the grade to go to our leading universities, but go elsewhere.

"This suggests perhaps a lack of ambition, but certainly a potential waste of talent."

He added: "Our leading universities should fairly reflect the ability of the whole population, not just the small minority whose parents can afford to send their children to independent schools.

"There are, of course, many excellent and academically demanding courses at other universities but those who graduate from our leading universities are more likely to have better social networks, better jobs and higher salaries."

A Department for Education and Skills spokesman said: "The evidence suggests that admissions are generally fair, but there is an inequality in applying to higher education in the first place.