There's a great mystery at the heart of the debate about the scarcity of young school leaders, which is: why, if morale among heads is as high as surveys suggest, does no one want a job in senior school management?
"I feel increasingly enthusiastic about my job," says Yasmin Bevan, head of Denbigh high, a multi-ethnic secondary school in Luton, Bedfordshire. "What we are doing now is incredibly empowering. I feel more energised now, after 15 years as a head, than at any time before."
"In no other job can you have so much influence over so many young people,"
says John Dunford, general secretary of the Association of School and College leaders (ASCL), which held a conference earlier this week to try and drum up enthusiasm for the job. Anecdotal evidence, as well as the findings of a recent newspaper survey, suggests that heads, on the whole, love what they do. But at the same time figures from the National College for School Leadership suggest only 10 per cent of middle management want to lead their schools.
The answer, it seems, is the negative perception of a job where accountability and workload can stifle independence and professional satisfaction. The ASCL conference was intended to show that, far from adding to the burdens of school leaders, new educational reforms can make their jobs more exciting and worthwhile.
"It is a great challenge," says Ms Bevan, "but it's a great opportunity too, to offer young people more."
She agrees that her job has changed over the years, but she denies that today's heads are more managers than teachers. "This is about leadership, not management," she says. "The new initiatives are not disparate: they all point in the same direction, so the key is to get people around you to make them work, to pull together. We heads are lucky to have people like business managers, who simply didn't exist years ago. Having staff who understand the big picture makes all the difference."
A competent senior management team is clearly good for the head, but, says Ms Bevan, good for the people in it too. She warns ambitious young leaders not to cede to pressure to move up through senior management to headship until they have fully understood how each post works.
"Give yourself time to do each job well. It's not in your professional interests to move up to a headship before you've mastered each stage on the way."
Above all, she emphasises that the days when a head's school was their castle have passed. "With extended schooling, you just can't do it on your own any more," she says.
Bob Mitchell, vice-principal of Beauchamp college in Leicestershire, with responsibility for extended services at the school, agrees. He says that his school has been led to review the whole way it operates as a result of embracing extended schooling, "and the buzz of working in a school like this is something I've never come across before," he says.
Mr Mitchell believes that new qualities are vital if the leaders of tomorrow are to seize the opportunities for change. As well as the usual requirements cited by selection panels - that leaders should be innovative, visionary and prepared to listen - he also believes that they must be prepared to take risks.
"Be prepared to go for 'glorious failure'," he says. "Don't beat yourself up for failing on some targets. I am lucky: my principal gives me the freedom to approach my targets in this way."
His belief that good support is vital for effective leadership is one that Ms Bevan endorses, although she argues that there can be too much of it.
"There's so much advice out there. You need someone who can help you weave a way through it to what is really useful for you - someone who can make the job look effortless but who has known, as we all have, those dark and dismal moments when you think, 'I don't want my school to be like this'."
Mr Mitchell sees the fast-changing nature of schooling as a thrilling opportunity rather than a threat. As those schools that run extended services reach out to the community, he says, they should also develop a new openness towards listening to, and learning from, outsiders. It's an openness that needs to come from senior managers.
Beauchamp college is a high-performing specialist technology school. Its examination results speak for themselves: last year more than 70 per cent gained top GCSE passes, despite the school being large (2,000 pupils) and more than half its pupils coming from ethnic minorities.
Beauchamp can risk innovation because of its success. It is harder for heads in a struggling school to take new risks, knowing that they may not bear fruit immediately. Yet that is often what they need to do to drive through change.
Recent government proposals, says Mr Dunford, make this an even less attractive option for heads. Local authorities will have powers to send in a management team, with a 15-day notice period, to take over schools judged to be under-performing.
"The 15 days' notice heads get is absurdly short. It just adds to the pressure on them. This will make it even harder to recruit," he says.
Ian Gilbert, of Independent Thinking Ltd, a company that produces motivational training for teachers, favours the Jammie Dodger theory of education. He believes that, like the eponymous biscuit, what children get out of school is made up of two parts: the biscuit ring is the way it is delivered; the jam "heart" of the biscuit is the emotional and social growth of the child at school, which enables him or her to flourish as an adult.
But the analogy could extend to school leadership itself , he believes - the outer ring of training and experience enclosing the inner "jam" of vision, innovation and risk-taking which is necessary, not only to become a successful leader, but also to be someone who enjoys the job.