But some myths must be dispelled. The shiny new buildings are not, for the most part, replacing failing schools as ministers have claimed. Not one of the 18 due to open this autumn is officially classed as failing, as the investigation we publish today (pages 6-7) shows. Our analysis last year reached a similar conclusion. Teachers are understandably indignant when politicians dismiss as “failing” schools that inspectors say are making good progress or have “many strengths”.

Yet if the new schools bring much improved education for children in some of the poorest parts of the country, few people will argue. Why, as one academy head said recently, shouldn’t the most deprived children be taught in the best buildings and the best schools?

At present, though, there is precious little evidence that ministers and the academies’ founders will realise their dreams. Alan Johnson, the Education Secretary, is putting a brave face on a government-commissioned report from PricewaterhouseCoopers which shows that the differences between academies and other similar schools are small. Test results at some are worse than at the schools they replaced. Innovative teaching methods - one of the reasons for giving academies more freedom than other state schools - have not worked.

Worryingly, the proportion of pupils in academies eligible for free school meals fell, in some cases sharply, between 2002 and 2004. A better mix of pupils in inner-city schools would help both teachers and pupils. But if the academies become middle-class enclaves that turn away the very pupils they were designed to help, the Government will have lost the argument - at a cost ofpound;5 billion to the taxpayer. Mr Johnson is right when he says that parents should not have to accept failing local schools. Neither he nor anyone else knows yet whether the academies will provide the answer.