The devolved governments have been largely excluded from the process of defining the UK’s approach to Brexit and its negotiations with the EU, despite early promises by Westminster to the contrary.

Instead, the devolution dimension has been dominated by the broader domestic implications of exiting the EU, with a particular focus on the EU (Withdrawal) Bill. As well as repealing the Act that took the UK into the EU, the bill is designed to avoid a ‘cliff-edge’ exit by converting existing EU law into domestic law—to be known as ‘retained EU law’.

The manner in which the bill deals with repatriated powers in devolved areas has led to a fierce battle between the UK government on the one hand, and the Scottish and Welsh governments on the other, with backing from cross-party committees within the Scottish Parliament and the National Assembly for Wales.

The Acts that created the devolved institutions required devolved laws to be compatible with EU law – a requirement that will lapse once the UK leaves the EU. The now infamous Clause 11 of the withdrawal bill includes a new constraint.

This effectively requires devolved law to be compatible with ‘retained EU law’ after Brexit and prohibits the devolved legislatures from passing laws to modify retained EU law, even when these are in areas of devolved competence.

The bill provides a procedure for loosening this constraint where it was agreed that a common policy approach across the UK is unnecessary. In the face of considerable and widespread opposition to this clause, the UK government has now introduced an amendment in the House of Lords requiring a minister to introduce regulations specifying the areas where this constraint on devolved powers would be applied. Analysis published recently by the UK government suggests that restrictions would be mainly in the areas of agriculture, fisheries and the environment.

However, this amendment has been rejected by the Scottish and Welsh governments. Fearing a ‘power grab’ which would undermine their devolution settlements, they have passed ‘continuity’ legislation to prepare their own statute books for Brexit while protecting devolved powers.

There is some doubt (including from the Presiding Officer of the Scottish Parliament) about whether these bills fall within the legislative competence of the devolved institutions, and the Supreme Court may be asked for its ruling.

That stage may not be reached though; both the Scottish and Welsh governments insist their first preference is to agree with Westminster an amendment to the withdrawal bill that could facilitate common UK frameworks without undermining devolution.

This is a fast-moving situation with an uncertain outcome, but the ongoing discussions and debates provide insight into the challenges and opportunities which are likely to continue to shape intergovernmental relationships in the months and years to come. The current political furore over fisheries policy during the transition period and beyond illustrates the complex political dynamics at work.

First, the current impasse in part reflects the absence of shared understanding of the extent and limits of devolution. From the UK government’s perspective, the fact that devolved law has had to be compatible with EU law means that areas in which the EU has enjoyed legislative competence have never been devolved.

Thus, repatriated powers that are passed on to devolved institutions will represent a considerable increase in devolved powers.

Viewed from Scotland and Wales, by contrast, all policy fields that are identified as falling within the competence of the devolved legislatures, according to their founding legislation, are already devolved, irrespective of whether they have been the subject of EU law.

In October, the three governments included a commitment to ‘respect the devolution settlements’ among the principles that would underpin new common UK frameworks to replace EU frameworks. But they hold different views of what that means.

Second, much of the ongoing dispute is about process rather than outcome. All governments are agreed that there will be some areas where it makes sense to operate on a uniform basis across the UK (or Great Britain, where separate arrangements make sense for Northern Ireland). For the UK government, common frameworks are necessary to preserve the UK’s internal market.

While some cross-border frameworks may be secured through less formal arrangements, such as intergovernmental Memorandums of Understanding, some may require UK legislation so that the same rules and standards apply in the same way across all four nations.

This, according to David Lidington, the cabinet office minister overseeing these negotiations, would ensure free movement of goods and services within the UK “without any extra red tape or expense”.

For their part, the devolved governments have recognised the need for some UK common frameworks and are as keen as the UK government to avoid new internal barriers to trade and mobility. Even in the context of Scottish independence, the SNP stressed the desirability of maintaining some common regulatory frameworks with the UK government. The issue is about who gets to decide.

The common position of the Scottish and Welsh governments was succinctly expressed recently by Mark Drakeford, the cabinet Secretary for Finance and lead minister in the Welsh government in the Brexit negotiations: “The things that are to be retained at the UK level should be things that are agreed… what we’re looking for is agreement… the principle of agreement, rather than the principle of imposition, is fundamental to us.”

Of course, these issues of process are not unrelated to concerns about outcomes. Although all governments share the desire to avoid barriers to trade, they may have divergent views on how this would best be achieved.

The Brexit negotiations have also revealed both the opportunities and the limitations afforded by the UK’s territorial constitution. The withdrawal bill is Westminster legislation, and it is for the Westminster Parliament to determine its final content and scope.

But early in the process, the UK government conceded that those clauses of the bill that most directly affect devolved competence would be subject to the Sewel convention, which commits it to seeking the consent of the devolved legislatures before the bill becomes law.

This does not amount to a devolution veto. As the Supreme Court confirmed in its judgment in the Miller case, the Sewel convention is a matter of politics, not a matter of law.

But by acknowledging the applicability of the Sewel convention, Westminster gave the devolved governments an opportunity for influence in intergovernmental negotiations beyond their constitutional authority.

Those negotiations have shifted significantly the UK government’s position, as evident in its amendment to Clause 11, even if not yet to the point where the devolved governments are willing to recommend consent for the bill.

If consent is withheld, the normal procedure, according to the convention, would be for the offending clauses of the UK bill to be removed, freeing up space for devolved legislation. However, given the importance that the current UK government attaches to retaining authority over the UK internal market, it seems unlikely that it would acquiesce on this occasion.

On the other hand, there is discomfort in the UK Parliament, especially in the House of Lords, at the prospect of passing the withdrawal bill without the consent of the devolved legislatures. The Scottish and Welsh continuity bills are an alternative to consent for the UK bill and add yet more constitutional complexity to the domestic Brexit process.

Clearly, their introduction is also intended to increase pressure on the UK government towards further concessions in its own legislation to a point that would render devolved continuity legislation unnecessary.

Dealing with the devolution effects of Brexit has also revealed both strengths and weaknesses in the UK’s intergovernmental relations. Informally, the extent of collaboration between the Scottish (SNP) and Welsh (Labour) governments has been unprecedented and key to their capacity to exert influence over the UK government.

Officials across the UK have been engaged in intensive collaborative work to explore where and how EU competences intersect with devolved competences, and where common frameworks may or may not be necessary.

These positive experiences of informal cooperation are set against the weaknesses of formal intergovernmental machinery, both with respect to its ad hoc nature and the hierarchical role that the UK government continues to enjoy.

This presents challenges in the context of Brexit, where the overlaps between devolved and reserved matters are set to become more acute, increasing the likelihood of policy overspill and disputes between the UK’s governments.

The Welsh government has been at the forefront of demands for, and thinking on, stronger and more equal intergovernmental forums and procedures which could foster more formal cooperative working.

This is perhaps because the Welsh government, as the least powerful of the devolved administrations, has most to gain from formalising shared governance, and most to lose from the alternatives.

More effective intergovernmental working which gave the devolved governments a stake in UK matters may be key to securing the stability of the UK’s territorial constitution.

Yet, there is little evidence of enthusiasm among UK ministers for such reforms, especially if they would impose constraints upon parliamentary sovereignty and on their ability to take back control.

By Nicola McEwen, Research leader at The UK in a Changing Europe and Professor of politics at the University of Edinburgh. You can read the full report ‘Article 50 one year on’ here.