In recent months, Professor Barber has emerged as Labour’s most influential schools adviser, the main architect of its policy on raising standards in inner cities.

The disclosure that Professor Barber and his wife Karen intend to select a school for their 11-year-old daughter Alys from a list of three independent schools and one selective grant-maintained school has generated further charges that Labour is guilty of hypocrisy.

The decision by Professor Barber comes after the revelation that Labour’s health spokeswoman Harriet Harman intends sending one of her sons to a selective grant-maintained school. Labour’s leader, Tony Blair, sends his son to the grant-maintained London Oratory, six miles from his home.

Professor Barber acknowledges that his admission that the family are considering non-state schools makes his role in advising Labour more difficult.

He says: “The goal for policy for state education has to be to make schools good enough to attract parents who simply want the best education for their children. I am aware that the decision we are making makes that less likely. Every parent that opts out makes the improvement of state comprehensive schools more difficult.”

Michael Barber, dean of new initiatives at London University’s Institute of Education, admits he and his wife differ over education. He is expected to remain on the governing body of Haggerston, a girls’ comprehensive in Hackney.

David Blunkett, leader of Labour’s education team, dismissed criticism of Professor Barber, insisting he was neither a politician nor a policy-maker.

However, the well-publicised school choices by senior Labour figures are likely to put further strain on the party’s policy commitment to comprehensives.

Mr Blunkett wants to concentrate on policies that create greater choice within schools, to stave off powerful voices in favour of specialist schools that might include selection on academic grounds.