State school pupils do better at university than independent school candidates who have achieved the same A-level grades, a study shows.
The Higher Education Funding Council (Hefce) tracked 130,000 students beginning degrees in 2007, looking at schooling, background and ethnicity.
It found on some measures state pupils were significantly more likely to get a 2:1 than their private school peers.
Private schools said a bigger share of its pupils overall got a 2:1 or above.
The Independent Schools Council highlighted figures in the report showing that 67% of independent school pupils achieved a 2:1 or above, compared with 62.3% of state school and college pupils.
But when students with the same A-level grades were compared, the results were different.
Of those students who achieved ABB at A-level, some 69% of students from independent schools went on to gain 2:1 or a above compared with about 77% of students educated at state schools.
And at three Bs, 61% of independent students pupils got a 2:1 or above compared with 70% of state school students.
Prof Madeleine Atkins, Hefce chief executive, said the findings confirmed an earlier study by her organisation.
But she stressed that this research, tracking around 80% of English-based undergraduates starting at all UK universities in a single year, was the most comprehensive of its kind.
The findings are important because it adds to the debate about how universities select their candidates.
Nearly all universities use what is known as "contextual data" to decide which candidates should be offered a place.
This is when those from state and other backgrounds are made lower offers, in terms of the A-levels required for entry to courses, than private school counterparts.
The idea behind this is that these pupils have not had the advantages of a private education but still have potential and should not miss out because they did not go to private school.
Prof Atkins said the report showed that independent school candidates came into university with better A-levels but that they were performing less well by the end of their degree courses. But she would not offer any explanation as to why this may be the case.
She said: "The study presents a robust and independent set of findings to inform discussion and debate, and to stimulate action. Further work - by Hefce, by the sector and by government - will be needed to understand why these effects are happening, and what sorts of interventions will be most effective in bringing about positive change."
But Barnaby Lenon, chairman of the Independent Schools Council, said: "Dividing the school population into 'state' and 'private' is too crude to yield anything of value.
"The majority of our pupils' A-levels were graded A or A* last summer and we note that Hefce, despite their best efforts, are unable to show that our pupils did less well at university than other groups."
Dr Wendy Piatt, director general of the Russell Group of high-performing universities, said: "As the report reiterates, A-level and equivalent qualifications are still, without doubt, the key source of information about academic ability.
"Students with better A-levels do better in higher education. But Russell Group universities take a range of factors into account when deciding which students are offered a place.
"So the candidate's qualifications are considered in a broader 'context'. The bottom line is we want to give places to the pupils with the qualifications, potential and determination to succeed."
The study also found that students from disadvantaged areas tended to do less well than those from more advantaged areas - even though they had achieved the same A-level grades.
Prof Les Ebdon, director of fair access to higher education, said: "This important research shows that a student's background influences their likely degree outcome.
"This is a worrying finding, suggesting that disadvantage continues to follow disadvantaged young people, even after they have overcome often significant barriers to get into university."