Headship is a lonely and emotionally-demanding job, to which only 8 per cent of teachers aspire.
This dramatic finding is revealed in a major and long-awaited report issued this week, which foreshadows a potentially serious crisis in the recruitment and retention of high-quality headteachers in Scotland.
Commissioned by the Scottish Government, the study found that 22 per cent of male heads and 24 per cent of females would not recommend headship to anyone. Overall, more than half - 53 per cent - said they would not urge others to go for the top job, or were not sure.
The chief reasons were their long hours and the demands of accountability to inspectors and local authorities. The majority of heads said they worked for more than 50 hours a week, with 45 per cent spending up to 65 hours on school-related tasks.
Six out of 10 heads said experience of inspection was a significant factor in their dissatisfaction, specifically "unfair, or unbalanced, representations of the school and too public an exposure of weaknesses".
The "emotionally-demanding" nature of the job was a concern for nearly 70 per cent of heads; 72 per cent worried about the impact on their lives outside work; and 46 per cent said it was lonely at the top. A further 72 per cent blamed the "public grading of school performance" for their disillusion.
The research, carried out by a team from Cambridge, Edinburgh and Glasgow universities, canvassed the views of 1,137 heads and 1,218 teachers. Almost three-quarters of teachers - 73 per cent - said they had no intention of pursuing the official route to leadership, the Scottish Qualification for Headship.
John MacBeath, professor of education at Cambridge University, who led the study, said: "The vividness of the language used by heads in their interviews to describe the task of leading a school is testimony to the emotional nature of the work: `fire-fighting'; `battles'; `ground down'; `frazzled'; `washed out'; `sucking people dry'.
"At the same time, `passion', `exhilaration', `commitment' and `pride' were recurring themes. One head described having a `love affair' with the school, another as having `an emotional relationship with the school' and another as `being married to the school'.
"This deeply personal investment in their schools (`my school') tells the story of headship and explains why frustration looms so large in their accounts."
Although Education Secretary Fiona Hyslop has signalled the importance of this study in several speeches - and initially promised to publish it 11 months ago - her department does not appear enamoured of the findings which were given a low-key release yesterday on the Scottish Government's website, with no political fanfare.