Academy schools, introduced by the Government in an attempt to raise standards in deprived inner-city areas, are being hijacked by middle-class families, research suggests.

A five-year study by the consultants PricewaterhouseCoopers has found that although academies still admit far more children from poor homes than most state schools, the proportion of those pupils has declined significantly in the past five years.

Between 2002 and 2007 the number of academy pupils eligible for free school meals, considered the bench-mark of poverty, rose from 6,600 to 8,000. But as a proportion of all academy pupils, the number of such children declined from 42 to 35 per cent. Nationally, the proportion has declined from 15 to 13 per cent over the same period.

The changes suggest that middle-class parents are being attracted to academies, having previously gone out of their way to avoid the failing schools they were replacing, the report says. “Whilst this suggests that there is now greater choice and diversity for these families, there is also a danger that their greater ability to manoeuvre within the market may disadvantage more socially deprived pupils,” it adds.

The findings highlight the difficulties facing the Government in narrowing the performance gap between rich and poor children. Any school thought to be half decent will inevitably attract sharp-elbowed middle-class families, keen to take advantage of services intended to boost standards among the less well off.

Academies – state-funded schools independent of local authority control and backed by private or voluntary sector sponsors – were set up to transform education for children in the poorest areas of England, who would otherwise attend failing comprehensives. The first three opened in 2002. Sponsors were expected to invest up to £2 million in each, but they can now offer services in kind instead.

The report includes data on the performance and backgrounds of almost 23,000 pupils at 27 of the first academies to open. It concludes that academic standards in academies have risen overall, although the scale and pace of progress varies widely.

This boost in performance and investment has made academies increasingly popular with parents. There are now three applications for every Year 7 place. As they have become more popular, some academies have introduced a “fair banding” admissions system which includes a test.

Results are grouped into ability bands and the academy will then admit a fixed proportion of pupils from each to ensure a good mix of abilities.

The report raises the concern that holding tests outside normal hours can disadvantage children from poor homes where parents work at weekends or have transport difficulties. It recommends that tests be held in school hours in local primary schools.

The report says that academies often benefit from the expertise of sponsors, but raises concerns that trustee boards contain too few women and people from minority ethnic groups. However, being free from local authority control gives flexibility on curriculums and hiring and firing, it says.

Christine Blower, acting general secretary of the National Union of Teachers, said it was extraordinary that the proportion of pupils from socially deprived backgrounds should have declined in academies.

David Laws, the Liberal Democrat schools spokesman, said: “The Government must make sure that where there is admission by banding this is implemented fairly.”

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