Diolch, Llywydd. Just about everyone can agree that leaving the European Union is a step of massive importance for Wales and the UK as a whole, and in a whole range of ways. The EU we will leave is much bigger and more complex than the Common Market, which we joined all those years ago, and it’s precisely because of this that leaving is an even bigger step than joining was. So, the challenges are many. They have been thrown into sharper relief by the general election result, and this, in my judgment, makes it inevitable that the UK Government will have to radically reshape its approach to this most crucial issue of the day, and, dare I say it, move closer to the balanced and coherent position set out in the joint Welsh Government and Plaid Cymru white paper, ‘Securing Wales’ Future’.

Of course, I welcome the fact that the first meeting between the UK Government and the European Commission yesterday went well, but this is just the first step on a long and complicated journey. Members will be clear that, for the Welsh Government, it is securing jobs and the economic prosperity of our nation that is right at the top of our agenda for Brexit. That has not changed and will not change. But today I want to focus on the implications of leaving the EU for devolution, and for the future governance of the UK.

Llywydd, first off, while acknowledging the result of last year’s referendum, let’s also remind ourselves that devolution is itself the product of two referendums here in 1997 and again in 2011: in the second of these, two thirds of voters voted in favour of the Assembly acquiring powers over primary legislation.

I hope we can agree across this Chamber that devolution, as endorsed in those referendums, represents the settled will of the Welsh people and is not something to be treated lightly by the UK Government, any more than it could ignore the EU referendum result. We roundly reject the UK Government’s assertion in the White Paper it published before the election that devolution is in any sense premised on UK’s membership of the EU. On the contrary, the demand for devolution is a freely expressed ambition of the Welsh people and the fact of EU membership at the time when devolution began was, in that sense, a purely practical feature of our arrangements. The task now, therefore, is to acknowledge the force of the various referendums by finding new arrangements for governing the UK that give practical effect to Brexit while taking full account of the permanence of devolution in the UK constitution.

The document before us today, ‘Brexit and Devolution’, builds on ideas we first tabled in ‘Securing Wales’ Future’, published jointly with Plaid Cymru back in January, and is the first of a series that will explore key issues arising from Brexit. There’s much to think about and discuss and that’s why we aim to stimulate debate here in the Assembly and beyond.

Leaving the EU will create new governance challenges here. We don’t yet know for certain how far, if at all, we will continue to align UK regulatory networks with those of the EU after Brexit, or whether we will remain in a customs union with the EU. But it’s certain that co-ordination of policies, which has previously taken place in Brussels, will, at least to some extent, need to be developed at home.

We readily recognise, for example, the need, in the exercise of our own powers, to work with the other administrations to develop binding UK-wide frameworks in a number of devolved areas to prevent friction entering into our own internal UK market. Four wholly different and incompatible animal health regimes, for example, would clearly be in no-one’s interests. Equally, there are UK competences in which we will have a clear Welsh interest.

So, we will need new and better ways for the various Governments to work together. But the existing consultative JMC machinery is simply not fit for the new task in hand. The right way to manage this business is through new and refreshed inter-governmental machinery. The four Governments must sit around a table to negotiate and agree binding UK frameworks in devolved areas where these are necessary, or in the short term each agree, of our own volition, not to make any changes to the current EU-derived frameworks, if that is needed.

The same machinery should facilitate discussion and agreement on non-devolved polices in which we will clearly have an interest, such as state aid and, particularly if we are outside a customs union with the EU, international trade. We propose in our paper a UK council of Ministers, along lines partially similar to the EU version. If it’s possible for 28 Governments to reach decisions in common areas, it should certainly be possible for the four Governments here in the UK to do so.

This is not an attempt to increase the powers of the Government or this Assembly. Again, the previous UK Government’s White Paper gave a wholly misleading impression that, in the work of developing frameworks at EU level that applied to devolved policies, such as the common agricultural policy or environmental policies, the UK Government alone determined the UK position. That’s simply not the case.

On the contrary, the UK Government is obliged by the memorandum of understanding, updated and ratified by this Chamber in 2013, to consult with the devolved administrations and develop a UK position that reflects agreement between all four administrations. It would be ironic if, in a UK in which we have, as it was put, taken back control from Brussels, the devolved institutions have less, not more, influence over the frameworks in which we operate.

If the UK Government is open to developing machinery that enables the four Governments to take forward common business in a collaborative way, they will find in the Welsh Government a willing partner. But let me be clear, if they do not, if they wish to impose frameworks or to legislate in Westminster to put new constraints on this Assembly’s powers and competence, we will resist them every step of the way, using all the tools available to us. As I’ve written to the Prime Minister, this is a fight that, now, of all times, she does not need.

Let me reiterate: we want legislation at Westminster, whether that be the great repeal Bill or an equivalent, which is a success in achieving the UK Government’s goals—providing legislative continuity and certainty and ensuring that, on day one after we leave the EU, our regulatory environment is identical to that of the EU. That is our first ambition.

But we require such legislation both to respect devolution and trigger the joint working we hope will facilitate a constructive collective future. If it fails to do this, if it tramples on devolution, then we will, of course, have to respond forcefully and negatively, and we are already in the process of developing our options for this eventuality. One primary responsibility of the Welsh Government, and indeed this Assembly, is to uphold the devolution settlement for which our people voted. I hope that message is heard clearly and noted in Whitehall.

We also think the time is right for a convention on the future of the United Kingdom. It’s an idea I have canvassed previously ad nauseam, as have others, but it is a matter of increased urgency now. Leaving the EU is a big step that requires a big response at home. It’s a natural position from which to think afresh about what kind of country and what kind of union we want to be for the long term. The convention should involve all voices, all political parties, civil society and all parts of the UK. And as I have said many times, the Welsh Government has plenty of ideas but no monopoly of them.

Let me be clear, then, Llywydd: I’m positive about our union. I want the UK to be flourishing, dynamic and well governed. I want the inter-governmental relationships among the four administrations to promote the dynamism that our union should show. Acting in the name of Welsh voters, we deserve something more than a grudging transactional relationship based on a bare minimum of fig-leaf consultation. Each administration needs to respect the political legitimacy and the mandate of the others in approaching this debate. Through discussion and co-operation, good ideas can develop into better ideas, and everyone wins. An effective United Kingdom helps all and hurts none.

It’s true to say, Llywydd, that the UK remains deeply divided. The way to heal those divisions is through respect and working through problems together—trying to see other people’s point of view. Secrecy, lack of consultation, imposition of diktats from the centre—these will do nothing to build the mature, dynamic, multifaceted and outward-facing UK that we can be. The paper we have published is intended to contribute to the thinking now needed to meet that challenge, and I commend it to the Assembly.