Described as the “Cromwell of his profession”, Mr Woodhead broke the mould of past chief inspectors, who had never gone so far as to lambast teachers en masse.

But how much responsibility for the current inspection regime can he really claim?

He cannot be said to have set up the system of four-yearly school inspections. That dates back to the first 18 months of the Office for Standards in Education, established in 1992. Mr Woodhead arrived in September, 1994.

In fact Anthea Millett, one-time deputy chief inspector whom Mr Woodhead narrowly beat to the top job, was the true architect of the current system, said a former senior inspector.

Tom Wiley, now chief executive of the National Youth Agency, said Ms Millett - who left OFSTED to lead the Teacher Training Agency - supervised the introduction of inspection standards and a new training regime for inspectors.

But Mr Woodhead’s influence in OFSTED on becoming chief inspector was, according to another former senior inspector, pervasive. Colin Richards, a critic of OFSTED who left the organisation in 1996, said the agency became Mr Woodhead’s “personal fiefdom”. “It was an auto-cracy,” he said.

That does not mean he was always successful in influencing Government policy. One reason advanced for his resignation this week was his frustration that ministers did not go for far more radical reform of local authorities.

However, Ms Millett this week said MrWoodhead’s championing of English and maths skills in primaries had helped bring about recent dramatic test improvements. She told The TES that he had made a “very substantial impact” in this area.

The son of an accountant and a school secretary, Chris Woodhead attended Wallington grammar school in Surrey, read English at Bristol, did a PCGE, going on to teach English at several schools and later on at Oxford University to trainee teachers.

He became an English adviser in the early 1980s and later deputy chief education officer in Cornwall and Devon. His first national job, in 1991, was deputy chief executive of the National Curriculum Council. He rose to chief executive within a year.

In 1992, while still at the council, he was appointed by former education secretary Kenneth Clarke as one of the “three wise men” to write an influential review of primary education. In 1993, he was appointed head of another quango, the School Curriculum and Assessment Authority, before becoming chief inspector the following year.

But last year, his seemingly relentless rise almost ground to a halt after he told an audience of student-teachers that relationships between a teacher and a student could be “educative”.

When his former wife then alleged that he had had an affair with a sixth-former, while teaching at her school, the education world expected him to be sacked.

But he rode out the storm - reportedly with the backing of the Prince of Wales and the Prime Minister. By last summer, he was even talking excitedly about the prospect of OFSTED’s forthcoming expansion into further education and early years.

Quite what happened to dull that enthusiasm and led him to resign continued to be a cause of some speculation this week.