Though most headteachers will be appalled at the thought, Estelle Morris was the second Education Secretary they helped to bring down in recent years.

John Patten never recovered from the humiliation he suffered when they (illegally) refused to carry out national tests. And Estelle Morris, though probably the most popular education minister since Shirley Williams, was fatally wounded by their concerted action over this year’s A-levels.

The hue and cry the heads raised was not the only reason for her departure. But it was what gave her most sleepless nights and its mishandling was the most damaging of the blunders for which she shouldered responsibility. The heads’ associations did not seek her resignation. Nor could they have foreseen it.

What is important now is not recrimination but the implications of their actions. It shows the latent power of those who actually run the education service as opposed to the ministers and officials who think they do and who ignore the warnings of those on the ground at their peril. In law, headteachers, governors and education authorities are responsible for running schools. Yet since Kenneth Baker, ministers have increasingly acted as if they were in operational control.

Education was once regarded as “a national system locally administered”. In those days ministers declined to comment on anything that could be passed off as the responsibility of the local authority and never ventured into the “secret garden” of the curriculum. Nowadays ministers seem to think they should decide what should be taught and how, what skills are required by teachers and headteachers, and how they should be paid and managed. They tell local authorities and schools how to spend their money. And they order that fewer children be excluded in the interests of inclusion. Or there again, a few moons later, that more should be excluded to maintain discipline.

Now they seem to have decided that giving a primary pupil a qualified teacher for four-and-a-half days a week rather than five represents an improvement in standards.

Ministers either attempt to control such things directly or through their appointed agents: the Qualifications and Curriculum Authority, the Teacher Training Agency and the National College for School Leadership. They may be outside the department but ministers select their executives and governing bodies and officials sit in on their deliberations and approve their press releases.

The media scrum over A-levels shows what an important consumer issue education has become. And that in turn makes it a burning political one. That is why the Department for Education has seen its press office grow from a staff of six in 1988 to 25 today. Press releases doubled under David Blunkett.

The night Estelle Morris resigned, citing her difficulty with modern media as one reason, distraught porters at her Westminster HQ hurled abuse at doorstepping journalists: “Haven’t you lot done enough harm already?” Yet almost the first act of her replacement was to welcome, glass of wine in hand, 40 or so journalists into her old office. This press attention adds to the de facto power of ministers. But it also adds to their vulnerability, as Estelle Morris found. Ministers seeking the credit also risk the blame.

The former Cabinet Secretary, Sir Richard Wilson, observed on his retirement earlier this year that all governments in the past 20 years had felt the need to engage in perpetual campaigning, even between general elections. As a result, he said: “Central government is now held responsible for the quality of services delivered locally - education for instance, or policing - even though statutorily and constitutionally they are not primary responsibilities of central government.”

So control brings with it culpability. Strength can also be weakness. The appointment of the tough, no-nonsense Charles Clarke underlines Tony Blair’s determination to get a grip on education. But it also signals his desperate need to show improvements before the next election.

Mr Clarke will come under the same pressure as David Blunkett and Estelle Morris to inflict yet more Blairite change on reform-weary schools. But he should also remember that headteachers can also have the ear of the press.

It was heads’ press conferences that forced a 13th-hour rethink of A-level reforms, demonstrating ministers’ dependence on the professionals rather than their powers over them. If the DfES could not efficiently administer its own QCA and three compliant exam boards, how can it hope to keep 24,000 autonomous schools onside?

To paraphrase that old saying about leading a horse to water, you can give a headteacher online access to Circular 898 Target-setting in Schools but you can’t make her read it, let alone act on it. And rightly so. Heads serve the communities that appoint them, not the Government. With their governors, they are there to determine and protect their pupils’ best interests, not to meet ministers’ needs for fast results.

Mr Clarke needs the profession’s support if he is to modernise its working practices and show improvements in a hurry. If political urgency and his self-assurance tempt him to overlook this, he may find those who run schools have ways of reminding him.

Bob Doe is editor of The TES