WANDSWORTH plans to challenge a ruling which would reduce academic selection in its schools.
The south London council says a government-appointed adjudicator exceeded his powers by ordering three secondaries to reduce the proportion of pupils they select after complaints from parents.
Up to half the intake of Ernest Bevin, Graveney and Burntwood schools is admitted on ability.
The Schools Adjudicator ruled in August this should be reduced to 25 per cent because tests were denying places to local children and damaging other schools by "creaming off" the brightest.
Wandsworth is calling for a judicial review, saying the adjudicator came to a decision before he had the full legal power to do so.
The High Court is due to consider the application for a judicial review on January 12, the day before Wandsworth pupils take selection tests.
But no new objection could be ruled on until the next academic year, possibly giving the schools up to two years "breathing space".
Wandsworth's education chairman Malcolm Grimston said: "Having a diverse system of schools, where some are partially selective, works. It has helped raise standards for pupils of all abilities. We see them as part-selective and part-comprehensive."