High-attaining comprehensive school students are significantly less likely to attend top universities than their independent school rivals with the same grades, new research has revealed.
Students at some of the country's leading comprehensives with the equivalent of at least three A grades are a third less likely to go to one of the UK's 30 most selective universities than their peers at independent schools, the study says.
According to a report by the Sutton Trust, fewer than six out of 10 students from the top 30 comprehensives went on to study at the country's leading universities, whereas for the 30 highest-achieving independents the figure was nearly nine out of 10.
The figures come alongside the startling statistic that just four independent schools and one college together sent more students to Oxbridge than 2,000 schools combined over the three years covered by the study.
The report states that Westminster, St Paul's and St Paul's Girls, all in London; Eton, and Hills Road Sixth Form College in Cambridge secured 946 places at either Oxford or Cambridge between 2007 and 2009, as opposed to 927 from 2,000 sixth-forms or colleges.
Lee Elliot Major, director of research and policy at the Sutton Trust, said: "A lot of the stark inequalities in university progression is driven by school results, but we have examples of schools with similar results but very different proportions going to the leading universities.
"There may be lots of different reasons for that: it might be different types of subject mix, the advice and guidance might be very different at the schools."
The Sutton Trust data shows repeated incidence of schools in the same regions with similar results but very different progression rates to the top universities.
Two schools in Cornwall, comprehensive Wadebridge School and independent Truro School, had near identical results, but Wadebridge sent 14 per cent of its pupils to the most selective universities, whereas Truro sent 58 per cent.
Brian Lightman, general secretary of the Association of School and College Leaders, said there were still too many barriers that prevent able students from applying to the leading universities.
"If you are taking the Oxbridge entrance route, the whole culture is very unique for a pupil from a background which is not used to it," said Mr Lightman.
The Russell Group, which represents the 20 leading research universities in the UK, said the report relied too heavily on Ucas points as a measure of academic success, which failed to show which subjects a student had taken for A-level or for which course they had applied.
Director general Wendy Piatt said: "Russell Group universities are committed to attracting students with the most potential from all backgrounds, which is why we invest millions in bursaries and other initiatives designed to help the least advantaged have the best possible chance of winning a place."
Geoff Parks, director of admissions at Cambridge University, agreed that looking at average Ucas points only was flawed, but added that schools needed to be more proactive. "It is about the quality of exams not the quantity. Often independent and grammar school students are achieving better results with a smaller number of exams," Dr Parks said.
"But some schools, like Cockermouth in Cumbria, have a great deal of contact with us and are extremely aspirational for their students."
A source close to education secretary Michael Gove said the study revealed further evidence of Labour's "failure on education".
"Despite all their talk their record is of letting the poorest children down who were too often left with the worst schools," the source said.
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