RECORD A-level results sparked fresh controversy yesterday, after the pass rate rose for the 25th year in succession.

For the first time, more than 25 per cent of exam entries were awarded A-grades, while one in ten students earned straight As.

The result was overshadowed by figures that showed A-grades were increasing far faster in private schools and selective grammars than in state comprehensives.

Independent schools said their freedom to ignore the Government's education policies helped them produce better grades.

Nearly half of all A-level entries in private schools were awarded As.

But in state comprehensives, fewer than one in five grades was an A.

Jonathan Shephard, of the Independent Schools Council, said one factor behind the success was the independence private schools enjoyed.

He said: "The ability to teach children above and beyond the national curriculum and, at times, to ignore the national curriculum is very important.

"It gives teachers at independent schools a greater degree of professional freedom, and that does look to benefit the children."

He said that part of the success of private schools was because they attracted better qualified teachers than many state comprehensives and that pupils wanted to work hard.

Figures from exam boards showed that in 2002, 41.3 per cent of A-level exam entries at independent schools were awarded an A. That rose to 47.8 per cent of exam entries this summer. But in state comprehensives, only 19.4 per cent of A-level entries were given A grades this year, up from 16.5 per cent in 2002.

Dr Mike Cresswell, head of England's largest exam board, AQA, said that if exams were becoming easier, there would be improvements across all schools.

He said: "Whatever the usual grumpy old persons want to say about how it used to be much harder in their day, what we want to say is congratulations to the students."