But inspection became part of the school furniture long before the Office for Standards in Education celebrated its 10th birthday this term.

Ofsted can reel off a mind-boggling array of achievements during its first decade.

However, chief inspector David Bell is keen to focus on one: more than 250,000 pupils now receive an acceptable standard of education after their school’s failings were identified by Ofsted.

“In some ways it is easy to forget the seismic shift in the education system represented by the creation of Ofsted,” Mr Bell said.

The service can trace its history to 1839, when two people were appointed as the first of Her Majesty’s Inspectors (HMIs) and began visiting publicly-funded schools in England.

But it took 153 years, and the 1992 Education Act, for Parliament to approve regular visits by teams of independent inspectors to all state schools in England.

Ofsted was formally launched as a non-ministerial government department on September 1, 1992, and began recruiting and training more than 10,000 registered, team and lay inspectors.

For the first time schools were inspected by a universal set of standards. Controversially they faced “special measures” if they were deemed to be failing.

Professor Stewart Sutherland, now Lord Sutherland, was the first head of Ofsted. But it was Chris Woodhead, the second chief inspector, who brought the role to greater public attention when he took over two years later.

Mr Woodhead swiftly became a bete noir of the teaching profession, after calling for the naming and shaming of bad staff, and claiming that at least 15,000 teachers were “failing”.

Individual local authorities such as the London borough of Hackney, which he described as “the worst-run council in Britain”, also came in for outspoken attacks.

Mr Woodhead denies that his views were based on his political prejudices instead of evidence. (In this week’s Sunday Times he wrote that “Inspectors who pontificate in an unconvincing way are, I agree, irritating”.) Mike Tomlinson, his successor, was applauded by Ofsted staff when he told them he would base all his comments on evidence.

Within the past two years the number of staff at the watchdog has doubled as it has taken over inspecting childcare and further education. More expansion is expected next year, when it pilots inspections of 14 to 19 education.

Teaching unions remain critical but a TES survey this year showed that teachers’ attitudes to Ofsted have grown increasingly positive since the departure of Chris Woodhead.

That view is shared by Education Secretary Charles Clarke, who said: “There is now far more appreciation that Ofsted inspections are a positive assistance to heads seeking to improve their schools than an ordeal of fear.”

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