An estimated 60,000 teenagers in every year group never make it into higher education even though they rank in the top 20% academically in school tests and exams.

And most quit before even taking A-levels, the report by the Institute of Education and the Institute for Fiscal Studies said.

The researchers suggested that if this untapped talent were to stay on in education, the proportion of young people going to university would jump 25%.

The study for the Sutton Trust charity followed figures that showed Oxford and Cambridge were taking an increasing share of students from wealthy private school backgrounds.

The Institute of Education's Dr Anna Vignoles, who led the research, said: "It has long been argued that there are financial and social barriers at the point of entry into higher education which prevent poorer students from going to university.

"This research shows clearly that the main reason why poorer students do not go to university to the same extent as their wealthier peers is that they have weaker academic achievement in school."

The academics used Government data to track the progress of one year group of 600,000 pupils in England. A significant number of pupils who were in the top 20% academically - aged either 11, 14 or 16 - did not go on to enter university by the age of 19.

Pupils from the poorest backgrounds - who were eligible for free school meals - were far less likely to attend university than those not on free school meals. But poorer students who reach A-levels were as likely to go on to apply for degree courses as their better-off peers.

Higher Education Minister Bill Rammell said said the Government was committed to "unlocking talent" and making sure any pupil with ability goes to university.