Last week, the office confirmed that inspectors would be including information such as the number of children on free meals and other social factors as part of their evaluations. This would allow comparisons between schools sharing similar circumstances. From April, The TES was told, factors such as the educational level of local population and ethnic mix would be included in inspectors’ initial briefings. Such innovation naturally made front-page news.

But in a letter published in today’s TES, chief inspector Chris Woodhead denies the story, blaming his own office for misleading the media.

He confirmed OFSTED is considering ways of comparing like with like, but went on: “When OFSTED reports reveal time and time again that low expectation by teachers of their pupils’ abilities is a prominent feature of unsatisfactory teaching and achievement, it is essential that OFSTED does nothing to encourage the use of pupils’ backgrounds as an excuse for poor performance.”

When league tables were first introduced, they were denounced because difficult inner-city schools were competing with those in the proverbial leafy suburbs. But Kenneth Clarke, the then Education Secretary, said parents needed raw, not cooked, data.

It was Sir Ron Dearing, in his interim report on the national curriculum, who said estimating value-added performance in league tables was a good idea and asked Newcastle University to do the research. Their interim report, which looks at tracking the prior attainment of pupils, said there was scope for secondary schools but it was more difficult for primaries.

OFSTED also commissioned London University’s Institute of Education to do some analysis based on social background. Last November, OFSTED held a seminar inviting several academics to discuss the evidence. A paper by Chris Bryant, OFSTED’s head statistician, based on the institute’s use of such criteria as numbers of free school meals and children with special needs was discussed.

Although there was disagreement about some criteria, the conclusion was that the basis of the paper was the way forward. OFSTED confirmed to The TES that the criteria would be used in school inspections from April. This has now been contradicted by Mr Woodhead.

According to one source at the November seminar: “It seems a power battle is going on within OFSTED. Either Mr Woodhead has been got at by the politicians, or he does not agree with it himself.”

nThe apparent disagreement within OFSTED emerged at a time of tension between Mr Woodhead and some staff. The First Division Association, the inspectors’ union, has received several complaints about the chief inspector.

A spokesman said: “A number of members are concerned that Mr Woodhead’s behaviour is damaging the professional standing of the inspection service. We are considering these remarks, but it would have to be an individual inspector who makes a complaint to the Civil Service Commissioner.”