The Office of the Schools Adjudicator, which considers disputes over admission policies, says that selecting pupils because their parents or grandparents attended could be in breach of race relations legislation.

The adjudicator, upholding a complaint against St George's School in Hertfordshire, said the "admissions criteria are not in the interests of local parents and may conflict with the provisions of the Race Relations Act 1976".

In the lastest series of rulings on admissions policies, the adjudicator also upheld complaints concerning a number of schools where preference for selection was being given to children whose parents worked there.

There were also reductions imposed on the proportion of pupils allowed to be selected on grounds of ability, with Watford Girls Grammar being required to reduce its number of pupils selected on the grounds of aptitude from 50% to 35%.

Right to selection upheld

These "partially selective" institutions are state schools, which are allowed to operate a selection policy for a proportion of their intake - on grounds such as academic ability.

After accusations that the independent adjudicator was setting a pattern of acting against selection, the latest batch of rulings also includes cases where rulings have upheld the right to limited selection.

In the London Borough of Croydon, objections had been made to selection policies in five secondary schools - with four out of the five complaints largely rejected.

But in St Joseph's Voluntary Aided College an objection from the local education was upheld against the practice of giving preference for places on the basis of past family links with the school.