Last June the UK voted to leave the EU. Or did it? In actual fact the results highlighted a divided country, with Wales and England voting to leave and Northern Ireland and Scotland voting to remain, the latter by a significant margin of 62% to 38%. As a result, immediately following the result, Nicola Sturgeon, Scotland’s First Minister, said that it was now “highly likely” that Scotland would have another independence referendum. Subsequently, on Tuesday the Scottish parliament voted to seek permission for another referendum and Sturgeon is expected to formally request a section 30 order from the UK government later this week, a move which would allow a referendum to go ahead.

The increasing acrimony over Brexit between both parliaments centres around three key issues, as yet unresolved. Firstly, the status of devolved powers that are repatriated from the EU following the negotiations. Secondly, the possibility of Scotland receiving a bespoke Brexit deal. Thirdly, the willingness of Westminster to allow the Scottish government to play an active role in the negotiating process.

Since 1973, when the UK joined the European Economic Community, Scotland’s political status within the UK has changed dramatically. From the original 1998 Scotland Act to the 2016 Act, Scotland has gained increasing power over a range of devolved areas, including education, policing, housing and, more recently, welfare benefits and income tax.

Importantly, though not always well understood, many of these competences were devolved to the Scottish parliament precisely because they were under the jurisdiction of the EU. What happens to these powers once repatriated is far from clear. The Scottish government sees this as an opportunity to expand its competences and create a differentiated position from the UK on a range of issues, such as fisheries and farming.

Unsurprisingly the UK government has a different view, with Theresa May saying pointedly that the government will decide the “right powers” to be repatriated to Westminster and Edinburgh. May’s government will be desperate to ensure that the Brexit negotiations do not unwittingly result in a massive transfer of powers to Scotland, skewing the inter-governmental balance within the UK.

The issue of a separate deal for Scotland is perhaps even more contentious and a key driver for another independence referendum. In December the Holyrood government’s proposals on a bespoke deal for the country outlined that Scotland should be given a soft-Brexit deal, allowing for continued membership of the Single Market, continued free movement of people and a guarantee of the rights of EU citizens north of the border.

The UK government has rejected this position, with Theresa May responding that she has a mandate to deliver a Brexit deal “for the whole of the UK”. The SNP has interpreted this as a sign that the Prime Minister is not prepared to work with Scotland on the negotiations (which, given May has been reluctant to involve even the UK parliament, is a position not without merit). Sturgeon has suggested that if Scotland does vote to leave the UK, it will have been the fault of the Conservatives, who are “dragging” Scotland out.

Finally, the issue of a bespoke deal has been exacerbated by failings in the mechanism for allowing Scotland to participate in the decision-making process. The Joint Ministerial Committee (JMC) is the body which is being used to ensure the governments of Scotland, Wales and Northern Ireland are informed of and have an input into Brexit developments. However Sturgeon has suggested that the UK government is not dealing with Holyrood in good faith, complaining after the last JMC meeting in January that “I don’t know any more now about the UK government’s approach to EU negotiations than I did before I went in”. Sturgeon’s dissatisfaction with the JMC, which appears to be shared by the heads of the Welsh and Northern Irish governments, could radically undermine May’s ability to present any final EU settlement as a truly UK deal.

As a result of these factors, it is clear that the debate with Westminster will centre, not on whether another referendum takes place, but when. The timings outlined by Sturgeon – late 2018 to early 2019 – are based on the assumption that Scotland should make a decision before the EU negotiations conclude, in order to allow it to re-join as quickly as possible. This is anathema to Westminster however, which will push for a vote some time following the negotiations, so as to avoid fighting on two fronts.

Over the past 20 years, the unionist gamble that devolution would “kill nationalism stone dead”, as George Robertson, then Shadow Secretary of State, famously said, has failed miserably. In the wake of July’s referendum result, the issue looks more alive than ever. Far from settling the UK’s future, Brexit has triggered yet another constitutional crisis and an ongoing standoff between Westminster and Holyrood.

By Peter Headden