There are more vacancies for head teachers than ever before. More than 1,000 schools are looking for candidates to replace an outgoing head, and as many as one in five will struggle to find one. The problem is more acute in primary schools and in secondaries that are seen as difficult. Scan the lists of ads and you can see the same school appearing three weeks in a row.
Part of the problem is undoubtedly demographic. Teachers are ageing. But many are choosing to take early retirement, weary of presiding over initiative after initiative. Others who leave blame the increased threat of litigation, while some point the finger at Ofsted. Whatever the reason, a significant number of head teachers want out while they still have time to enjoy life.
Yet it may not just be the stress that is causing hesitation among those who ought to be waiting in the wings. Part of the difficulty may be that the role of the head teacher has changed, and become less attractive to potential applicants.
The Government has done much to make the job more professional. Would-be heads must do the National Professional Qualification for Head teachers - being a magnificent history teacher, for example, does not necessarily equip you to run a school. All job specifications now insist that candidates have at least started the course, if not actually finished it.
Labour has also established the National College of School Leadership, which, among other things, is designed to provide ongoing support for head teachers. The word leadership in the title is crucial here. All the research literature on effective schools suggests that heads should not be simply managers but also leaders, providing the school with educational vision. At the same time Labour's accompanying rhetoric implies a desire for heads to be both entrepreneurs and innovators.
The problem is that everything else Labour has introduced makes this kind of leadership increasingly difficult. There is little if any room for curriculum innovation. Even specialist schools, much vaunted by the Government, have timetables that look much the same as everyone else's, while national tests dominate every stage of the school curriculum. An entrepreneurial head cannot, for example, opt out of this assessment regime in order to improve the quality of learning for the pupils in his or her charge.
In addition, much of the increased funding for schools is not allocated straight into the budget, but has to be applied for. The need to produce elaborate proposals turns head teachers into glorified fundraisers, and uses up much of their valuable time.
The heightened power of the school governor under Labour also makes it difficult for head teachers to feel in control. This disparate collection of individuals, with vastly differing skills, oversee the running of the school on a voluntary basis. In this capacity they have the power to block any initiative a head may introduce. Keeping them onside can be a tedious business that stifles change.
These same governors are responsible for appointing the head teacher. This may be the final reason that schools are not attracting the type of head that the Government seems keen to promote. Placing arguably the most significant appointment of any school in the hands of well-intentioned amateurs, who may have neither educational or personnel expertise, is an odd way of promoting professionalism. True, many seek the help of the local authority. But this means that a prospective head has to fill in the same form as a teacher looking for their first job. Governors often depend on what they know, which means either an internal candidate or the "safe pair of hands" will succeed.
Schools need leaders who are creative, and are prepared to be bold when necessary. At the moment, the headship of a school seems more trouble than it's worth for the cautious, and too constraining for the entrepreneur. Labour's actions satisfy no one, and until their policies change, schools will not get the leaders they require.
The writer is a lecturer in education at King's College London