Wandsworth Borough Council in south-west London was told by the Office of the Schools Adjudicator to cut academic selection in the schools to 25% following complaints from parents at local infant and junior schools.

But the council argues the admissions watchdog did not have the power to make the ruling, because it would significantly change the character of the schools.

It says that at the time the ruling was made in the summer, regulations delegating powers from the Secretary of State had not come into effect.

It is now seeking a judicial review of the decision, and will mount its legal challenge in January.

'Significant change'

Of the three Wandsworth schools which use academic selection tests, two admit 50% of pupils by academic ability, while another admits 30% of children in this way.

The council says that when the three former comprehensives, Ernest Bevin, Graveney and Burntwood, first applied to become partially selective, the decision was referred to the Secretary of State because it represented a "significant change of character".

It argues that ending partial selection would also be a significant change in the character of the schools.

It says it accepts the watchdog now has delegated powers to make such a decision, but says no new objection could be ruled on until the next academic year, possibly giving Wandsworth schools "up to two years breathing space".

Wandsworth Council's education chairman Malcolm Grimston said: "We have shown in Wandsworth that having a diverse system of schools - where some are partially selective - works. It has helped to raise standards for pupils of all abilities.

"These are successful schools. The council wants to preserve their right to select pupils to the extent they do today. We see them as part-selective and part-comprehensive schools within what is probably the most comprehensive system of secondary education anywhere in the country."

'No objections'

The council's case will be heard in the High Court on January 12, the day before all primary school pupils wanting to attend any secondary school in Wandsworth sit a new, unified entrance exam.

The council says the exam will give schools more information about pupils' ability on entrance than national curriculum tests, and will simplify the admissions process. It has dismissed suggestions that the exam is an attempt to extend selection by high ability.

The lead adjudicator, Sir Peter Newsam, would not comment on the details of Wandsworth Council's legal challenge.