Independent school pupils have increased their hold on places at the UK's 20 most prestigious universities.
Private schooling increasingly has opened doors to top colleges
The acceptance rate for private pupils who applied in 2006-07 to Russell Group universities - which include Oxford and Cambridge - rose from 62.5% to 65.6%.
The figure, published by the Independent Schools Council, is five times the average acceptance rate.
This is despite government efforts to promote a wider social intake in such leading universities.
The survey also found that the top universities preferred pupils with three very good A-levels, rather than a high combined points scores based on four or more exams.
The findings, from the Independent Schools Council's annual universities survey, show that independent schools are continuing to be successful in the numbers of their pupils being offered places in the most sought-after universities.
'Quality not quantity'
These figures show that almost two-thirds of applicants from independent schools in 2007 were offered a place at one of the 20 leading, research-intensive Russell Group universities.
Among subjects such as physics, biology and maths, the acceptance rate for private school pupils was more than 80%.
For comparison, on average only 13% of all applications to the Russell Group were successful last year.
An analysis of applications also shows that these leading universities prefer high-quality A-levels - such as three grade As - rather than a higher point score from four lower grades.
"Our research shows that A-level point scores can be misleading as a measure of achievement - it is quality, not quantity, that counts," says the council's chief executive, Jonathan Shephard.
In terms of applications, this high grades rather than high points preference is significant because independent schools are particularly strong in getting pupils to achieve three top-grade A-levels.
Provisional figures for this summer's A-level exam results show that 7% of pupils in comprehensive schools achieved three A grades, but in independent schools 30% of pupils achieved this benchmark.
A report published in the autumn by the Sutton Trust highlighted how independent schools continued to be over-represented in the top universities.
Only 54% of students at Oxford University and 57% of students at Cambridge are drawn from state schools.
There are about 510,000 pupils in independent schools represented by the Independent Schools Council.
Independent schools have about 7% of the school population - but this rises to 23% of pupils in sixth forms.