It is not just Mr Woodhead who has angered the unions, however: the man who said that 15,000 bad teachers should be sacked is simply the unacceptable face of an inspection system that has come to symbolise everything the profession hates most about the Government.
For teachers, the image of the year is the modern-languages teacher featured in a BBC2 documentary last November who broke down in tears as the inspectors delivered their verdict. Not because they had criticised her teaching at John Ellis Community College in Leicestershire; on the contrary, they judged it very good. But the stress of the inspection had simply proved too much for her.
So this week we shall hear union delegates call for members to break the law by refusing to talk to inspectors or teach while they are in the room.
Why are teachers so incensed? Inspectors have been visiting schools for more than a century. Though previous generations of teachers bit their nails when Her Majesty's called, they were accepted as an inevitable part of the educational landscape.
All that has changed. The Government's reforms cut the number of HMIs by more than half and replaced them with teams of privatised inspectors. The latter bid for contracts to inspect schools; these are awarded by Mr Woodhead's office.
The new system differs sharply from the old. First, schools are inspected every four years. In the past, some would go 10 years or more without seeing an inspector. Teachers who switched schools at the right time might escape inspection for even longer.
Second, the bottom line of an inspection has become more punitive. Previously, the worst that could happen was that the local authority, after receiving a bad report, might ease out the head, usually by moving him or her to an "advisory" post. Now, if a school is declared "failing" and is unable to convince Ofsted and the Secretary of State for Education that it can improve, it may eventually be closed down.
More recently, the Prime Minister decided that individual teachers might also be declared failures. They will be graded on a seven-point scale; those at the bottom will be reported to the head.
The inspectors themselves have changed. Thousands more had to be recruited to cope with more frequent inspections. Some were retired HMIs but many more came from the ranks of local-authority advisers who, on ministers' own admission, ranged from good to very indifferent.
Teachers point to the inspection team which criticised PE at a north London primary school that had regularly won prizes for sport. At a primary school in the south-east, inspectors said the pastoral system was not good enough; it turned out that, during their visit, teachers had not sent children to the head because they thought she would be too busy with the inspectors.
Ofsted argues that these were teething troubles. A report published by the office last year suggested that two-thirds of headteachers were happy with inspectors' judgements.
None of this will pacify the delegates in Cardiff or Glasgow. They believe that both the Government and the Chief Inspector are anti-teacher and that a system operated by them is bound to be unfair.