The congratulations could not, however, mask a couple of worrying developments: the increase in the overall failure rate and, in particular, a doubling of percentages failing in the crucial subjects of English and maths.

Schools, it was suggested, have concentrated on high-achievers at the expense of weaker pupils. In maths, meanwhile, a shortage of skilled teachers has been blamed for an unusually large drop in the pass rate.

Just over 670,000 pupils sat the maths GCSE but nearly 35,000 candidates failed to achieve even the lowest G grade.

“This is potentially very significant,” said David Reynolds, professor of education at the University of Newcastle and, until recently, chair of the Government’s numeracy task force.

“Many schools would support the view that the recruitment crisis in maths teaching has finally hit exam results.

“Fears about polarisation of results by league tables go across the board,but schools find it particularly hard to fill maths vacancies and many classes have to make do with ad hoc arrangements involving supply teachers or staff without any maths qualifications.”

Pupils who would previously have left school at Easter are another factor to influence pass rates. This year, for the first time, they were forced to stay at school and take GCSEs.

Professor Reynolds said: “This set of students may just have been poor raw material. The maths results in national tests for 9293 were particularly low compared to English and science. That gap had been narrowed by the time the cohort took GCSE, but may explain why the maths results were lower. This year could just be a blip.”

Maths was the core subject with the lowest proportion of candidates achieving A* to C grades, 46.9 per cent compared to 47.3 per cent last year. The failure rate increased from 2.1 to 5.2 per cent.

Annie Gammon, secretary of the Association of Teachers of Mathematics, believes the introduction of mental arithmetic tests at key stage 3 this year shifted teachers’ attention from GCSE low-achievers.

She said: “There is too great a load for teachers to give their very best to everybody. Maths teachers may have put too much into preparing key stage 3 rather than working with the lowest achieving GCSE candidates.”

David Burghes, professor of maths education at Exeter University, blames changes to the system of three tiered papers in maths.

This year, students who took the higher paper could get grades A* to C, but no longer a D. Similarly, intermediate paper entrants could no longer get an F, but were awarded grades from B to E. Pupils failing to fall within their paper’s grade band are given a U.

Professor Burghes said: “The tiering system has been a disaster. Schools are under pressure to get C grades for the league tables and there is a great temptation for them to enter pupils for the intermediate paper when they are really on the EF boundary. Then if they fail to get an E they get a U, which seems almost criminal.”

In English entries were down by 1.8 per cent and the failure rate doubled leaving 6,400 students without a grade.

Gabrielle Cliff Hodges, chair of the National Association for the Teaching of English, said this year’s GCSE English questions had been more narrowly focused and had not given pupils at the bottom end of the ability range the chance to shine.

Ms Cliff Hodges also blamed the shift from coursework to exams for the increased failure rate. She said: “Some people work better in a coursework situation and respond badly to the pressure of the exam room. Also this year the syllabus has changed so students must touch on a lot of areas, not necessarily in great depth.”

While overall there were 62,000 fewer GCSE exam entries, there was a marked rise in the number of modern language candidates. Two-year GCSE courses in French, German and Spanish attracted up to 8 per cent extra support. But while there were large increases in students getting the top A* grades, a slump in As and Bs saw fewer students overall getting top grades.

GCSE short courses were widely available for the first time this year: 207,887 candidates compared with 30,683 last year.

The biggest increase in GCSE entrants was the 150,000 sitting the now compulsory design and technology papers.