The move follows the overturning by the High Court of a decision by Philip Hunter, chief schools adjudicator, to reduce the percentage of pupils selected at two Hertfordshire schools.

Three other schools in the county had been waiting for the outcome of this judicial review, brought by Watford boys’ and girls’ grammar schools, before they launched their own applications for reviews at the High Court last Friday.

The Office of the Schools Adjudicator confirmed it has now dropped its order to reduce the percentage of pupils selected by aptitude and ability at Parmiters in Watford, Queen’s in Bushey, and Dame Alice Owen in Potters Bar.

A spokeswoman said the three cases were similar to those of the two Watford grammar schools and it was acting “in the interest of equity”, as a result of the judge’s decision. Dr Hunter had demanded in July that the Watford grammar schools cut the percentage of students selected by ability from 35 to 25 per cent.

In September, he accepted the schools’ decision to use different aptitude tests for music which they use to select a further 10 per cent of pupils.

Ernest Bevin school, in Wandsworth, London, is also seeking a judicial review this month. It will contest the adjudicator’s plans to reduce the proportion of the intake selected by ability from 33 to 30 per cent (equivalent to just six pupils).

The chairman of governors for Watford boys’ grammar school, Chris Brearley, is backing Ernest Bevin. He does not rule out the possibility of future challenges by the adjudicator but he hopes other schools will take heart from his school’s success.

“I would encourage other schools to stand up to the adjudicators,” he said.

“There is nothing else we can do as schools to protect our academic ethos.”

However, the judicial review route can be expensive, with one local education authority saying the bill for challenging the adjudicator could run into tens of thousands of pounds.