Grade seven is a level so unspeakably low and intuitively understood that it is accorded only the terse description “very poor” in OFSTED guidance. Whereas grade six is defined as “poor; a serious weakness; promotes very low educational standards and quality”.

The subjective division between grade six and seven clearly requires considerable insight into the abysmal depths to which teaching, in theory at least, might sink. The benefit of any doubts about such a distinction is ever likely to go to the teacher, however, given the limited time inspectors have to carry out the double-checks and additional head and teacher interviews a grade seven will trigger and the limited appetite they are likely to have for any ensuing disputes.

Even if some selfless inspectors do award a few well-deserved sevens, no one should imagine that a teacher risks the sack on the strength of such a judgment, or certainly not without the concomitant risk of a successful action for unfair dismissal. The head still has to go through the procedures of warning the teacher concerned, providing support, time and targets to give an opportunity to improve. Even the draft code recognises this and requires the registered inspector to point out to the head that “inspection information ... should not be used in isolation to justify action against the teacher. It should be seen as an additional piece of information.”

Those who have objected that such “additional information” is superfluous have missed what is likely to be the main practical impact of these reports, not on weak teachers but on weak managers. Ignoring teacher incompetence becomes that much less of an option if a head fears being confronted with evidence by inspectors.

That may not be a bad thing in itself, though it is questionable whether it is worth the ensuing distraction from the whole-school thrust of the inspection process. But then constructive improvement did not serve the political imperative of giving the Prime Minister a robust-sounding, teacher-bashing, headline-grabbing tub to thump at the opening of his autumn campaign to restore his own and his party’s public standing.

The shame of the once fiercely independent HM Inspectorate is that it has gone along with this politicisation of its function. Symptomatic of this is the covering letter with the draft code which begins: “As you know, the Prime Minister announced his decision to have inspectors report from April 1996 on teachers whose teaching is very good or very poor.”

The 1992 Education Act establishing OFSTED inspections says nothing about the Prime Minister issuing directions to inspectors. It requires the Chief Inspector of Schools to give them guidance and to “have regard to such aspects of government policy as the Secretary of State may direct”. No such direction has been given in respect of poor teachers.

HMCI Chris Woodhead made little secret of his agreement with the Prime Minister’s announcement. He is entitled to make such a judgment independently about inspections, and issue guidance accordingly. But why then does OFSTED lay the credit for it at the door of Number 10? Whether the answer involves partisan political support or an attempt to pass over HMI concurrence with this nonsense, neither is very creditable.