Since the first academies opened in 2002, parent and teacher campaign groups have complained that some are taking their freedoms too far. They argued that some were breaching pupils’ human rights by operating outside normal state school rules on admissions and exclusions.

But campaigners can take comfort from an investigation by The TES of the latest 19 academies, which opened in September. Documents obtained under the Freedom of Information Act show that sponsors are exercising considerably less freedom. Only one of the 19 has opted for the right to select 10 per cent of its pupils by “aptitude” for a particular subject - 12 of the 27 early academies did so. And all the new academies give excluded pupils the right to an independent appeal, unlike three of the earlier academies.

Policies towards religious education and collective worship are also more standardised with a new, shorter clause covering faith. It says RE must be taught in accordance with the locally agreed syllabus, unless they are designated as faith schools. A contract for one of the first academies, sponsored by Sir Peter Vardy, the evangelical Christian car dealer, said all lessons would be “consistent with Biblical teaching”.

The parliamentary joint committee on human rights warned this year that academies sponsored by evangelical Christian groups might indoctrinate pupils.

New academies also have a higher number of parents and local authority representatives on their governing bodies, watering down the power of sponsors.

David Wolfe, education lawyer at Matrix Chambers, London, who has represented parents in a series of high-profile court cases against academies, said: “It is a step in the right direction. Some of the rough edges have been taken off academies in terms of what they can and cannot do, but it is still the case that pupils and parents are less well protected than they would be in an ordinary maintained school.”

Heads of academies have defended their admissions rules, saying that they guarantee a wider social mix. The TES investigation showed that seven new academies operate “fair-banding” tests, which ensures a proportion of pupils are admitted across the ability range. The remaining 12 use more normal admissions rules, usually using distance to home as a tiebreaker.

Like specialist schools, academies can select up to 10 per cent of pupils by aptitude or potential in a subject, such as sport, music or languages.

Only one - John Madejski academy, a specialist sports college sponsored by the chairman of Reading FC - has opted for it, but is not yet using it because it is undersubscribed.

Catherine Shaw, its principal, said only 150 of its 180 places were filled this term, but this was twice the intake of the school the academy replaced. She said: “If we are oversubscribed in the future, we will select 10 per cent on ability. Our new intake has a much more even spread of abilities than in previous years.”

Policies on RE and collective worship are considerably diluted. While early academies outlined extensive policies towards faith, most contracts signed for the 19 new schools limit rules on religion to three paragraphs, saying they will abide by national laws.

The David Young community academy, Leeds, sponsored by the Church of England, says that while it is inclusive of all faiths, pupils should be able to use collective worship to achieve a “sense of transcendence”. Ros McMullen, principal of David Young, said: “We are a church-sponsored school, not a church school. Although we have a Christian ethos, it is multi-faith.”