Private schools help with university entrance, a study found

They were "significantly" more likely to get into leading institutions, including Oxbridge, than their state school peers, according to Professor Geoff Whitty, director of the Institute of Education, University of London.

This, he said, meant universities such as Bristol had been right to look at students' potential, as well as their A-level results.

His book, Education and the Middle Class, is based on in-depth interviews with 350 men and women from the time when they were at school until their mid-20s.

'More encouragement needed'

About half went to fee-paying schools and the rest to state grammars and comprehensives.

The private school pupils scored an average of just under a grade B per subject.

This equated to or 7.7 points under the old Universities and Colleges Admissions Services (Ucas) tariff, where an A was worth 10 points, a B eight, a C six, a D four and an E two.

Students who went to grammar school scored 7.2 points per subject and those who attended comprehensives gained an average of 6.5.

The privately educated pupils benefited from a more academically able intake and better facilities, said Professor Whitty.

By contrast, comprehensive schools had to educate children of all abilities, so pupils were arguably doing better given their environment.

The study said: "Elite universities should give more encouragement to those who gain slightly lower grades at comprehensive schools."

In 2002, Cambridge selected 56% of its UK undergraduate intake from the state sector. For Oxford the figure was 54%.

Bristol University's policy of seeking out the best state-sector pupils provoked private school fury earlier this year.

Head teachers decided to boycott the institution, although that measure is due to be lifted soon.

Philip Evans, head teacher of fee-paying Bedford School, said a difference of more than half a grade per subject was not small.

Across the usual "portfolio" of three A-Levels, it meant the difference between BBB and BCC.