With attainment targets getting tougher and pressure on school leaders becoming ever greater, warnings of a shortage of teachers willing to step up to become principals have grown in recent years.
And now, it seems, these prophecies have come to pass in England, with primary schools (for 5- to 11-year-olds) facing a potential recruitment crisis as many struggle to secure the services of principals.
Of the primary schools that advertised for a new principal in January this year, 26 per cent were forced to re-advertise within two months - up significantly from 15 per cent for the same period last year, and a higher proportion than in any year since 2000.
The situation is particularly severe in London, where almost half (44 per cent) of the primaries seeking a new principal had to re-advertise, more than double the 20 per cent rate recorded 12 months previously.
Russell Hobby (pictured right), general secretary of school leaders' union the National Association of Head Teachers (NAHT), said that many teachers are being put off applying for promotion by negative rhetoric about the profession from UK education secretary Michael Gove, as well as pressure from English schools inspectorate Ofsted and the threat of forced conversion to academy (state-funded independent school) status.
"It just shows the effect that the ratcheting up of pressure and hostile rhetoric is having in deterring people from becoming headteachers," he said.
"Being a headteacher is a wonderful job if you get the support you need but many teachers are worrying about feeling the hand on their shoulder. You need time to turn things around in a school but many school leaders are not confident they will have that.
"When you feel your achievements over the past decade have been belittled, that's why people don't want to take up the job."
The figures from Education Data Surveys, owned by TSL Education, the parent company of TES, reveal that primaries in regions outside London are also struggling to find new school leaders. In the South East, 38 per cent of principal posts had to be re-advertised, while in the East the figure was 28 per cent and in the East Midlands it was 27 per cent.
Emma Knights, chief executive of the National Governors' Association, said there has been a significant increase in the number of school governor members reporting difficulties in finding principals.
"We are hearing from school leaders that some people are less willing to put themselves up for headship because of the high stakes associated with the job," she added.
But while many principals cite inspections as one of the most stressful aspects of their job, the NAHT will use its annual conference, which starts today in Birmingham, to announce plans that could result in schools in England being visited by yet another set of inspectors.
The union is to launch its own school inspection service, "Instead", with a pilot version to start in the new academic year. Mr Hobby hopes the scheme will go national - and could in future actually replace Ofsted, which he described as "stultifying" and said was "damaging innovation".
He added that his union has taken inspiration from Finland, which used to have a formal inspectorate but replaced it with a model closer to what he is proposing.
"The pressures created by Ofsted are affecting schools' ability to improve," Mr Hobby said. "The first rung of the inspection ladder should be constructed by the profession itself."
The voluntary inspections are expected to last longer than those undertaken by Ofsted. Schools will be classed as offering an acceptable or unacceptable standard of education in terms of achievement, attainment, teaching and learning, as well as ethos and culture. They will receive continuing support to help them improve after the inspection.
Mapping cash flow
Average pay, in euros, for principals of state primary (aged 5-11) schools in 2011-12:
- 88,060 - Denmark
- 69,663 - US
- 62,488 - Italy
- 59,686 - England and Wales
- 57,618 - Finland
- 27,172 - Greece
- 17,944 - Poland
- 4,780 - Bulgaria.