Parent power is posing a threat to the academies programme with a big increase in the number of groups using legal advice to thwart the opening of the new schools.
The TES has learned that lawyers specialising in academies are considering an average of one new case a fortnight. The news came as Gordon Brown signalled his commitment to the controversial academies programme, previously closely associated with Tony Blair.
David Wolfe of Matrix chambers, the practice part-founded by Cherie Booth, the Prime Minister's wife, is now helping parents fight academy plans in around 20 separate areas. "A year or so ago there had been no legal opposition to an academy," he said.
Not all the cases end up in court. In Milton Keynes, parents are being advised on how to prevent the closure of Sir Frank Markham community school to make way for an academy, with an appeal to the schools adjudicator.
Mr Wolfe said parents' concerns tended to centre on good schools being closed and the lack of consultation about academy plans.
There were also reservations about accountability in the semi-independent schools and opposition to new money for local education being dependent on academies opening.
So far three parental challenges have reached the courts, involving academy plans in the London boroughs of Islington and Merton, and the Isle of Sheppey in Kent.
None resulted in a clear-cut victory, but Mr Wolfe believed they had influenced the way the Government handled the programme. "To its credit ministers have improved their decision-making process and the quality of the funding agreements (the document that sets out the rules for individual academies)," he said.
He added the Government's ad hoc approach had created more scope for legal challenge. "If you are going to do something that effects one in five secondaries nationally there needs to be detailed rules about procedure.
But the DfES have been making it up as they go along."
A DfES spokesman said: "Academies are very popular with parents and are heavily oversubscribed."