The future challenges of the education system almost all revolve around capacity. How will we create enough school places, attract and retain good teachers and encourage bold leaders? All in a period of budget cuts, growing pupil numbers and recruitment difficulties.

There is a serious risk of governments – and the profession if it responds in kind – fighting the last war, of believing that autonomy and high stakes accountability hold all the answers. Both these have a role to play but they are levers that have been pulled for so long that they are worn out. Indeed, some of the capacity challenges we face are direct consequences of the over-use of accountability and autonomy. We struggle to recruit talented leaders for the most challenging schools because of the level of capricious risk they face. We struggle with recruitment because, in devolving the responsibility, we have lost the ability to track the data.

It is now time to be clear that a successful education system rests on three pillars not two; that you must invest in capacity for people to rise to the challenge of accountability and to use their freedoms widely.

And this is going to sound quixotic but this is a fantastic opportunity for the profession. I know that many are feeling bruised by recent announcements, but the challenges of capacity are not easily solved by government. They are subtle, intangible, slow and hard to spin. Government will need to work closely with the profession. They may be feeling free of constraints with a new majority but they will quickly find that educational resources and the legacies of hasty reform are their secret coalition partners.

So, we do not shirk intelligent accountability, we welcome the power to make decisions that are right for our schools but we need investment in our capacity. We should ask for the resources we need, forcefully, but we must also take some responsibility for ourselves.

This begins with leadership. Inspiring Leadership is a great example of the profession taking control of its own development. The conference is now bigger, better and freer than when it was in government hands. We should go further and restore investment in leadership development. We should ensure that every new head and every new executive head has a mentor from within the profession.

A further step is in groups of schools. I do not believe that every school will be forced into a trust – those very forces of capacity stand in the way of this. But I do believe that every school should seek out a group of like-minded schools and join together in voluntary but purposeful collaboration. There should be a variety of “trust” and federation models and the profession should create them. We should be driven by the chance to make a difference with inspiring colleagues not by threats and incentives.

There is work we can do on QTS and a fairer funding formula but we should also keep up the pressure for reform of inspection. External challenge must remain part of the system, but Ofsted is too intrusive. We spend too long second-guessing the inspector instead of doing what we know to be right. We cannot reform assessment until we have confidence in Ofsted’s approach to data and progress. Because so much rests on it, the outstanding grade is a subtle constraint on those leaders who should be most independent and confident. We should aspire to outstanding for every school but we should not hand the definition of excellence to our regulator. The Ofsted reforms coming into effect this September are positive but we need more. And the spectre of capacity haunts even inspection – high quality inspection needs skilled and experienced inspectors: where will they all come from?

We have a simple mantra at NAHT: take ownership of standards and take responsibility for each other. This is a strategy, we hope, fit for the era of capacity.