This is the private inspection agency which last week accepted the blame for inserting controversial comments about resources - or the lack of them - into a report on Coleshill School in Warwickshire.

The episode caused embarrassment all round and led to allegations of political interference when these comments were later removed. This week, OFSTED promised to haul the agency over the coals.

“OFSTED takes a very serious view of the interference by the contractor with the inspector’s report,” said the director of inspection, Michael Tomlinson. “We will be meeting Open Book to discover exactly how this came about and what action we need to take. We will also take the steps necessary to ensure that no other contractor repeats the error.”

Although the chief inspector, Chris Woodhead, is the target of much political sniping from outside and within OFSTED, it would seem that there is no opportunity for him to vet individual school reports before they come out.

By law, OFSTED sees them only after publication; the reports are sent to the schools first. They are also numerous, at around 6,000 a year.

“There’s no opportunity to amend them,” said OFSTED spokesman Jonathan Lawson. “We try to monitor the quality of them. But only after the reports have been published.”

The kerfuffle over the Coleshill report was made possibly partly because so many current and former HM inspectors are hostile to Mr Woodhead, whom they regard as a political appointee.

There is, however, room for editorial influence in a different category of report: those produced by the HMIs rather than OFSTED’s registered inspectors. These tend to be generalising survey reports. Recently we have, for example, had reviews of inspection findings in all the main curriculum areas.

Such reports, as OFSTED acknowledges, are seen and if necessary altered by the hierarchy before publication. OFSTED says this would normally involve the original author.

In fact, there was a substantial degree of editorial influence in the days before OFSTED. While the chief inspector was, in the past, unlikely to see individual reports, he or she would certainly have seen the survey documents.

These in turn went to the Secretaries of State for Education who, as history shows, were more than capable of delaying reports or, if necessary, suppressing them altogether. A very encouraging survey of secondary education, for example, was held up for six months - until the 1987 Education Reform Bill had been published.