The House of Commons education committee criticised the Government for expanding the specialist scheme without proper evidence that it offers taxpayers value for money.

In a hard-hitting report on diversity in secondary education, the committee said the expansion may be based on “wishful thinking” and the lobbying skills of Sir Cyril Taylor, chair of the Specialist Schools Trust, rather than what works.

The report also attacks league tables for promoting the use of the proportion of pupils gaining five or more A*-C grades as “an inadequate and misleading measure of pupil achievement”. Recent research for the trust used the measure to show that pupils improve faster in specialist schools.

Barry Sheerman, Labour MP and chair of the committee, said the measure was “much too narrow”. “Grammar schools, for instance, are bound to get good scores. There would be something seriously wrong if they didn’t.”

But Sir Cyril described MPs’ proposals as nonsense. “Specialist schools’

first duty is to raise their own results,” he said. “Research shows they do that whether it is based on A*-C grades or on GCSE point scores.”

There are 1,224 specialist schools and the Government hopes all secondaries in England will take up specialisms.

But MPs said there was a “mismatch” between promises of diversity and the experience of parents and pupils.“The rhetoric on choice has, perhaps inevitably, not been matched by the reality,” they said.