Making popular schools expand damages their pupils' education and disrupts neighbouring schools, the first chief schools adjudicator has warned.
Sir Peter Newsam attacks Labour's core education policy in a letter in today's TES. He says encouraging schools to expand to meet parental demand is "misguided" and "not clever". The policy puts pressure on the facilities and the time teachers spend with the pupils already there.
"Why is it assumed that the happiness of 150 parents who get what they want should outweigh the unhappiness of 750 other parents who, as a direct consequence, do not?"
Ministers will find it hard to ignore Sir Peter's comments because he was the first person the Government appointed to make judgements on school admissions. The 76-year-old was chief schools adjudicator from 1999 to 2002, when he oversaw hundreds of disputes, many involving schools that wanted to increase their pupil numbers.
He was previously director of London university's institute of education, chairman of the Commission for Racial Equality, and chief education officer of the now-defunct Inner London Education Authority.
Pledges to help popular schools expand were a key part of both the Labour and Conservative election manifestos this year and will be part of the education white paper.
In his letter, Sir Peter describes how two schools with 900 pupils would be affected if one decided to increase its numbers. The expansion of the first would initially damage its neighbour's intake, but over time its intake could return to its normal level, leaving the expanded facilities unused.
"Does anyone with any experience of that process believe that encouraging schools to enlarge themselves at will would be anything other than an expensive way of achieving an unacceptable measure of disruption to other schools?"
His comments were supported by the National Union of Teachers' general secretary, Steve Sinnott, who said: "It is a very short-sighted policy. The popularity of schools is a matter of fashion."
The Department for Education and Skills said it would allow schools to expand only if they were certain the quality of education would not fall.