Schools are failing bright children by putting them in for exams too early, Sir Michael Wilshaw, the chief schools inspector, warns today.
Thousands fail to get top grades in their English and maths GCSEs because they are taking them a year early. As a result, they are likely to miss out on studying the subjects for A-level or at university.
Figures produced by Ofsted, the education standards watchdog, show the number of pupils being put in for maths and English GCSEs a year early has shot up over the past 10 years.
Between 2005 and 2012 the number of students put forward for early GCSEs in these subjects has risen from 9,000 to 241,000 in English and from 24,000 to 218,000 in maths.
The figures also show that, of the brightest pupils identified by national curriculum tests at age 11, only 37 per get an A* or A grade pass in English if they take the exam early. That compares with the 49 per cent who get top grades when they take the exam at 16. In maths, the figures are 43 per cent and 54 per cent respectively. Sir Michael, who is also head of Ofsted, said the figures revealed "the perverse incentive of the league tables".
"All heads are anxious about their position in terms of five A* to C grade passes including maths and English," he said. "In some ways this is a perverse incentive: making sure your five A* to Cs are as good as last year and are beating the school down the road."
As a result, schools are "banking" their most talented pupils' C grades a year early and then concentrating in the final year of GCSE preparation in pushing them through to C grades in other subjects. This approach could lead to them receiving no English or maths teaching in school after the age of 15, Sir Michael added.
Sir Michael also blamed "the curse of mixed ability classes without mixed ability teaching" for failing pupils. He said it was hard to cope with a disadvantaged pupil with poor skills sitting next to a "potential Oxbridge graduate" in the same class.
About 20 per cent of those in the top level at age 11 failed to get the A*, A and B grade passes their talent warranted, he said. "It is a combination of low expectations about what these youngsters can achieve and the curse of mixed ability classes without mixed ability teaching," he said.
"Heads have got to make up their minds. If they want mixed ability they've got to ensure there is good teaching. It must not be just an article of faith – comprehensive means mixed ability." Sir Michael said 6,000 schools teaching two million children needed to improve from their current ranking of satisfactory – now abolished under new inspection procedures – to good within four years.
"About a third of our schools are less than good," he added.
A spokesman for the Department for Education said: "Candidates entered early often perform worse overall than those who do not, even after re-sits are taken into account.
"Some pupils are being entered before they are ready and 'banking' a C grade but their performance at Key Stage Two [seven to 11] suggests that if they had continued to study the subject and taken the GCSE at the end of Year 11 [at 16] they could have achieved a top grade."
Science grade boundaries also changed
Grade boundaries in science were changed at the last moment at AQA (Assessment and Qualifications Alliance), it emerged yesterday. The pass marks for A*, A, B and C grades in chemistry and biology were lowered between the January and June sittings. Less than 1 per cent of biology candidates achieved an A* grade in January compared with more than 10 per cent in June. In chemistry the respective figures were two and 12 per cent. However, the lowering of the C grade in biology led to fewer candidates achieving it.