At the Unity academy in Middlesbrough, which failed its Ofsted inspection in May, just 6 per cent of pupils achieved the standard of five GCSEs including maths and English, by which all schools will be judged from next year.

The results raise questions over both Tony Blair’s plan to create 200 academies at a cost of £5 billion by 2010 and the White Paper proposals for “trust schools” that are modelled on a similar independent status.

There are 103 schools in England where less than a quarter of pupils got five A*-C GCSEs, but if those five subjects must include English and maths, the number of schools rises to 672, of which 13 are academies.

At Capital City academy in Brent, Philip O’Hear, the head teacher, admits that with 11 per cent of pupils achieving five good GCSEs, including English and maths, results are “low”, but says that comparing the results with other schools’ is hard because English is a second language for six out of ten pupils. He is confident however, that next year, when the first intake will have attended Capital for three years, results at Key Stage 3 will be much improved.

Academies make up a tiny proportion of the poorly performing schools, but because they cost, on average, £32 million to build compared to £12 million for a standard comprehensive, the results cast doubt on their value for money.

Yesterday Sir Cyril Taylor, the chairman of the Specialist Schools and Academies Trust, defended academies.

“They have to be given time to improve,” he said. “The best indicators of whether they are improving are attendance, Ofsted inspections, Key Stage 3 results — because it gives a snapshot after two years — and staff turnover.”

The Government has said that from 2006 all schools where less than a quarter of pupils achieve five A*-C GCSE grades, including GNVQs, face being put into “special measures” by Ofsted.

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