One GM head who was interviewed for a new study by University of Leicester researchers admitted: “I see all these statistics which claim GM schools are more successful than LEA schools ... We know you can make statistics look any way you want. You would have to make a comparison with what the school was like before it went GM. We don’t do that. We just compare results from GM schools with those from LEA schools and say (the GM results) are better.”

Another head expressed similar concerns: “I always thought (the issue of standards in GM schools) was a dodgy wicket because many of the GM schools were either selective or were well-managed and well-governed and were in the lead anyway.”

And a third head, after providing information about his school’s A-level successes, added: “They are better, but that has nothing to do with GM status.”

However, several of the six GM heads and six chairs of governors interviewed by Lesley Anderson and Tony Bush said that exam results were not the only measure by which schools should be judged.

One chair said: “We have tried to improve the environment ... and the general fabric of the school ... we have spent a lot of time ... to improve and hone the (staff) selection process ... the quality of people and leadership ... which has had a knock-on effect of improving standards of behaviour.”

And a primary head claimed that GM status had enabled her to expand the curriculum. Every pupil in her school was now offered instrumental music tuition, a range of languages including Latin, various sports and many cultural visits. Her aim, she said, was to see each child “not just travel, but fly”.

“Educational standards and grant-maintained schools: perceptions of headteachers and chairs of governors”, by Lesley Anderson and Tony Bush, is published in the latest issue of Educational Management and Administration, Sage Publications, 6 Bonhill Street, London EC2A 4PU. Tel. 0171 374 0645