Chris Woodhead, former chief inspector, asked his staff to rewrite a report on Birmingham to focus more on his adversary Tim Brighouse, then the city's chief education officer.
Documents, obtained by The TES under the Freedom of Information Act, have reignited a row between the two senior education figures over the Ofsted inspection in 1997.
Professor Woodhead insists that he did not ask Ofsted inspectors to alter any of their judgements.
However, the papers include a memo in which he demanded that extra information be added about Professor Brighouse. "Given the chief education officer's huge personal impact, we need, I think, a section on his style, leadership, etc," he said. "I say this because he deserves to receive the public recognition and because I worry about the transferability of the Birmingham approach - does it depend too much upon one very unusual man?"
Education officials in Birmingham had been concerned before the inspection that Ofsted's judgements might be biased because of animosity between Professor Woodhead and Professor Brighouse, who were both on the Government's standards taskforce.
Professor Brighouse had been highly critical of the inspectorate while Professor Woodhead was sceptical about the education director's liberal approach towards schools.
Professor Woodhead rejected a request by Professor Brighouse that he should have no involvement in the Birmingham report. But he promised he would only provide a "quality assurance function". "It may assist you to have my personal assurance that there is, of course, no question of my officiously inter-meddling," he said.
David Singleton, then head of Ofsted's local authority division, told Professor Brighouse in October 1997 that the chief inspector had no thought of altering the judgements.
However, the following month Professor Woodhead sent Mr Singleton a private memo demanding extra financial information about Birmingham so he could check the figures with a private accountancy firm, "if it can be done without getting the world to know," he said.
A fortnight later Professor Woodhead wrote Mr Singleton a three-page letter outlining a number of serious concerns about the Birmingham report including that many sections seemed "little more than a tissue of assertion".
He set out his own interpretation of the findings and demanded more investigation into Professor Brighouse and the local authority's vision for schools.
"You are questioning whether the rhetoric of this vision translates into improvements on the ground. You are asking (tacitly for the most part at present) whether the LEA could have done some things differently and why it has not achieved more. What I want you to do is expose the story more clearly."
Professor Woodhead then demanded that a range of additional information be found on Professor Brighouse and the city's strategies.
Professor Brighouse, now London schools commissioner, said: "I was never in any doubt that Woodhead was interfering in the report. He has chosen his words carefully. However, it is clear he went far beyond quality control."
Professor Woodhead is now chairman of the private schools firm Cognita and will rewrite the national curriculum if the Conservatives win next week's election.
"If you are suggesting I was trying to change the substance of the report, I dispute that view strongly," he said.
"The memo told the inspectors to work on the story they were already telling, but to explore it with maximum clarity."
WHO FAILED ISLINGTON GREEN? FRIDAY MAGAZINE 8