A level pass rates

Leading universities are split over whether to use the A*. Among the Russell Group, Cambridge has made A*AA its standard offer in most subjects, while Imperial has requested it in seven courses, UCL in four and Warwick in one.

But some top universities including Leeds have declined to use the A* this year, partly because of fears that private schools will perform disproportionately well. Oxford has declined to use it because of concern about the accuracy of teachers' predictions.

In 2009, more than 50% of A -levels taken by privately educated pupils scored an A compared with 20% of those in state schools, widening the gap in achievement between the sectors.

Today's results are the last A-levels to have been taken, in part, under a Labour government that came to power promising to transform education.

The rise in the pass rate over the last three decades has prompted concerns that A-levels have got easier while candidates' abilities have remained the same.

Research at Durham University has found that a candidate who would have got a C two decades ago would get an A now.

The study by Dr Robert Coe found that "candidates of comparable ability are being awarded higher grades each year, both at A-level where the trend has been consistent and substantial since 1988, and at GCSE."

The research was based on comparing A-level grades over the years with scores for tests that looked at general ability rather than curriculum knowledge.

Coe said it could be that exam performance had improved; there was more focus on preparation and schools were being more selective about who sits exams. Changes such as coursework or modules made it easier for today's candidates to shine with the same quality of work as in previous years, he said.

Meanwhile, Britain has slipped in comparison with other countries.

According to a respected international study, the OECD's Pisa survey, the UK fell from fourth in the world for school science in 2000 to 14th six years later. It slipped from 7th to 17th for reading and eighth to 24th in maths. The findings were based on independent tests of children's ability.