The government has signalled that specialist schools which champion one subject will get additional funding if they can take on another area of expertise.

Charles Clarke also suggested ministers had failed to communicate the successes of business-sponsored secondary schools.

Ministers also claimed that the Conservatives' education plans would allow head teachers to introduce a "five-plus" academic exam for children before they can get into primary schools.

Meanwhile Sir Cyril Taylor, the architect of the specialist schools policy, has said that every state secondary will be in receipt of private money by the end of the decade.