Colin Richards, primary specialist adviser at the Office for Standards in Education until last month, says in an article in the Times Educational Supplement that Mr Woodhead changed the way in which data was presented in his annual report so that he could claim that half primary schools needed to improve.
Mr Woodhead, whose office is independent of the government, has been the subject of a series of attacks from critics who accuse him of producing reports and making statements to support Conservative Party policy. He said last year that 15,000 teachers should be sacked.
But Mr Richards' outburst is the first attack from one of his senior colleagues. It is unusual for even a retired member of Her Majesty's Inspectorate to speak out in this way.
His article accuses Mr Woodhead of "politically inspired negative comments" and " highly economical use of registered inspector's judgements". Mr Richards left the standards office after another candidate was appointed to head the primary HMI team. He declined the offer of another senior job.
Mr Richards is said to disagree with Mr Woodhead's view that primary schools use too many trendy teaching methods and appears to believe that the Chief Inspector wants to paint a gloomy picture to bolster his call for a more traditional approach.
Mr Richards' main charge is that the annual report, the latest snapshot on the state of education, was based on misleading use of data.
He criticises Mr Woodhead's use of the seven-point scale on which aspects of a school's performance are judged. In last year's annual report, he says, the middle point, four, was judged to mean neither satisfactory nor unsatisfactory. This year, grade four was judged to mean in need of improvement. Had Mr Woodhead counted the middle grade as denoting satisfactory, around 90 per cent of primary schools would have been judged satisfactory.
Mr Woodhead explained his reasoning in an annexe to the report. He said the mid-point was used to show that neither strength nor weaknesses predominated. "Such neutrally judged features of a school may still promote sound achievement but the weaknesses identified in the reports on individual schools show them to be amenable to improvement. In this report, therefore, schools judged neutrally are included in the number requiring improvement."
A spokesman for the standards office strongly denied the accusations. "We refute everything [Mr Richards] says. It is nonsense. We have always denied the charge of political motivation . . . We should be doing a disservice to parents if we were to brush this kind of thing under the carpet and pretend everything was alright."Reuse content