One of the benefits of leadership is that you get to call the shots. One of the drawbacks is that it’s your head on the chopping block if things go wrong.

What leaders tell me, though, is that they are weary of working in conditions in which their head is never off the chopping block, regardless of how well or badly things seem to be going.

Leadership is a risky business. So risky, in fact, that our school leaders are saying enough is enough and are walking away before the axeman cometh.

The Department for Education quietly published its workforce data about school leaders a couple of weeks ago. Quietly is the operative word here, because it made for pretty depressing reading. It confirmed what other sources had already said - something that the government has been denying is a problem for a long time. Nearly a third of school leaders appointed as new secondary heads in 2013 had left by 2016, and for primary heads it was nearly one in five. The number of leavers is growing, too.

These statistics confirm what NAHT headteachers’ union members have been reporting for some time - that school leaders are leaving the profession or taking a demotion in large numbers.

In the NAHT’s “leaking pipeline” survey in November (see bit.ly/NAHTpipeline), respondents reported a rise in failure rates for recruitment to deputy and assistant head roles, with 78 per cent of deputy roles cited as being difficult or having failed to recruit. Seventy per cent of assistant head roles posed a similar problem.

Society asks much more of schools than a generation ago. Those aren’t my words, by the way. They were spoken by our current secretary of state for education at the NAHT’s annual conference in Liverpool at the beginning of the month. His speech struck a lot of chords with the school leaders in the conference hall. It was the first time we’d really heard anyone in government acknowledge that the weight of expectation placed on schools had just been getting higher and higher with each passing year.

Driving school leaders to the exit

From an academic perspective, schools are now teaching a more demanding curriculum. This is not a problem - it’s just everything else on top that drives some school leaders to distraction, and many more to the exit door.

I won’t get into the specifics here because unless I mentioned everything, I’d be in danger of artificially singling out or ignoring crucial things that schools are now doing in addition to teaching and learning. I suspect that school genuinely is the place where a lot of this activity should be happening. But, as more and more is being expected of schools and their leaders, funding and support is being cut. This creates more and more pressure. At the same time, the methods used to hold schools to account have become increasingly punitive. One bad year of test or exam results for your school can lead to the loss of your job.

This is the paradox of school leadership. Yes, you want to be in charge. Yes, you want to provide a multiplicity of opportunities accessible to young people of all backgrounds and abilities. Yes, you want your school to be the very place that sets in motion the best of all possible future lives for the pupils who pass through it. But if a lack of funding forces you to drop subjects or activities, or lay off staff against your better judgement, why should you get the blame if children’s options are narrowed? If the methods used to hold you and your school to account are so arbitrary and prone to misuse that they put a limit on your ambition, why should you have to pay for that with your job?

Responsibility is fine. School leaders accept that. But school leaders are not the only ones who bear responsibility for outcomes.

Government policies on funding, on curriculum, on assessment, all have an impact. Yet, it only seems to be school leaders who are ever held accountable.

With the system operating in this fashion, causing so many leaders to walk away, something needs to change. The recent announcement by the secretary of state that the government would look again at how it holds schools to account was an important and welcome move. I take him at his word when he says he wants to work with us. I was pleasantly surprised by Damian Hinds’ candour in Liverpool.

He acknowledged that inspection hung like a “spectre” over many schools. He admitted that the accountability system can sometimes drive workload. And, for the first time, he recognised that there were real cost pressures on schools, citing rising pensions and national insurance costs.

If we can make progress here, we will start to take some of the risk out of being a school leader. We will start to value the judgement of highly paid, experienced school leaders with in-depth knowledge of their schools, their staff, their students and their context - ahead of some stranger’s interpretation of data. And we will start to take some of the pressure off.

Paul Whiteman is general secretary of the NAHT headteachers’ union. He tweets @PaulWhiteman6