I knew I wanted to be a teacher from the moment I first stood in front of a class, which is why I’ve dedicated 38 years of my life to it.

As I prepare to move on to something new, I find myself reflecting on the state of our profession with a sense of optimism, accompanied by what I’d describe as a sense of personal regret.

When I started my first job as a “probationer” (as we used to call early career teachers), everyone told me it would be tough - and many questioned my career choice.

That familiar but degrading mantra “If you can, do. If you can’t, teach” was liberally bandied around.

Inconsistent training dependent on luck

It was hard and, looking back, I realise how unprepared I was. Some of my survival approaches now seem unthinkable. My generation’s training was at best inconsistent, and so much depended on luck. Some mentors and trainers were brilliant, others mediocre or entirely absent.

We learned through trial and error, and by sharing anecdotes and tips or observing colleagues - some of whom were good, but some of whom I now realise weren’t.

We helped some children, others we failed. We were permanently exhausted from all this effort, although for those of us who lasted, what was never lacking was a sense of collegiate solidarity.

What I now know we lacked was a body of properly curated, rigorous, shared professional knowledge that could have informed, shaped and directed our pedagogical and curricular approaches.

This could have drastically reduced the energy expended on well-intentioned but fundamentally misguided approaches.

A quiet revolution

Yet over the past few years, I’ve watched a quiet revolution in our schools.

A primary headteacher recently told me that for the first time in her career, all the teachers in her school are having meaningful discussions about their approaches to curriculum, pedagogy and adaptive teaching, remarking: “So many of the conversations happening before were teachers talking past each other.”

So what’s changed?

In that particular school, all members of teaching staff have completed either the early career framework (ECF) or a national professional qualification (NPQ) - whether for leading literacy, teaching, behaviour and culture, or teacher development.

These interlocking programmes have helped them develop a range and depth of knowledge so they can themselves improve, as well as challenge and support colleagues. This virtuous circle is the holy grail of school improvement.

But it’s not unique to them.

Making teaching an exact science

In the trust I lead, which has two teaching school hubs, staff have told me how accessing these programmes has revolutionised their understanding of teaching and curriculum organisation. They are genuinely conscious of this, and visitors see it, too.

This is where my optimism lies: we are on the brink of making teaching into a far more exact science than it has ever been before.

The government’s courageous decision to fund NPQs at the point of access, so there was no financial obstacle for schools, has enabled us to kickstart this groundbreaking programme of investment in teacher expertise. It has made it possible for these programmes to be taken at scale and it has attracted global attention.

We all know the challenging picture on school funding - and that hard choices may have to be made, by the government, schools and trusts.

Yet continuing to invest in teacher expertise through evidence-based professional development must be one of the priorities at all levels because it is the best tool in our toolbox for sustainably raising standards and closing gaps.

Creating teaching experts nationwide

Good professional development has real-world implications for children and young people. We need teachers whose expertise is deepened and strengthened over time - it’s no good sending them on one course and expecting the impact to continue.

We should do everything we can to make sure our current generation of teachers has the opportunity to keep shaping their practice in the light of well-marshalled and properly applied evidence, including from cognitive science. That’s what I call really investing in teachers.

Continuing on this path will enhance the status of teachers in our society. Rightly, they will be seen as not only subject experts, but as genuine teaching experts. Out of that will emerge the professional confidence to do what’s right for the young people for whose futures we are all responsible.

Together we are turning that old mantra on its head, and as I leave, if I can feel that I’ve played even a small part in helping this happen, that feels like the kind of legacy I’d be proud to leave behind.

Ian Bauckham is the chief executive of Tenax Schools Trust. He will be taking up the post of chief regulator at Ofqual from January