EU Referendum: Splitsville?

22 June 2016

The focus on the fall-out from Britain’s hypothetical messy divorce with the EU has largely dealt with the social and economic implications. However, the consequences of the fifth largest economy leaving the largest trading bloc will result in unprecedented uncertainty for Westminster, Whitehall, and the UK constitution. As Civil Servants grapple with could be the “biggest bureaucratic upheaval for a generation”, DeHavilland outlines the constitutional implications of EU Exit.   

The withdrawal process

Prime Minister David Cameron has confirmed that, in the event of a Leave vote, he would activate Article 50 of the Lisbon Treaty without delay, signalling the start of the process for the UK leaving the EU.

Vote Leave has also suggested that it could be possible to leave via Article 48 of the Treaty, detailing the process of revising treaties. However, this method could be blocked by a majority of member states, and amendments would require ratification by every member.

Nevertheless, activation of Article 50 would require Mr Cameron to inform the European Council of Britain’s intention to leave within a two-year period of negotiation. The Council is next due to meet on 28 and 29 June, but could meet sooner if a Brexit vote occurred.

The UK Government will then be tasked with concluding an agreement concerning its withdrawal, including setting out its future agreement with the EU. All EU treaties will cease to apply to the UK upon the conclusion of such an agreement or after two years from the declaration. But until then, the UK remains subject to obligations under EU law.

This period can be extended by agreement between the European Council and the UK.

The timing of the declaration therefore becomes key - Mr Cameron has indicated that he would begin working immediately to enact the process of withdrawing from the EU, but domestic economic and political factors could interfere. If no agreement is reached within the two-year window, the UK would automatically revert to World Trade Organization (WTO) trade rules.

The stages of negotiation, as the Alan Renwick of the Constitutional Unit has advised, would first focus on the terms of withdrawal, a trade deal with the EU and a negotiation with the WTO.

However, there could be several complications along the way. Chief among these concerns are the capacity of the Civil Service to handle such an administrative and legislative challenge, and a review of EU legislation. The FT reports on a potential major skills gap in Whitehall, and notes suggestions that outside law firms or consultancies could be hired.

Furthermore, former Clerk of the House of Commons Crossbench peer Lord Lisvane has argued that if Brexit wins by a small margin, a second referendum could be triggered.

A group of pro-EU MPs have already suggested they could use their Parliamentary majority to prevent the UK from leaving the Single Market, putting the negotiation process in jeopardy. More pressing, however, would be the impact of Brexit on the political union.

Legislative impact on the devolved assemblies

Brexit could have far reaching consequences for devolved settlements, as EU Law is incorporated into the devolution statutes in Scotland, Wales and Northern Ireland.  

For example, as Sionaidh Douglas-Scott has highlighted, the European Convention on Human Rights (ECHR) and EU law are incorporated directly into devolution law, and attempts to amend statutes or legislation would require the consent of the devolved assemblies.

If Westminster were to repeal the European Communities Act (ECA) 1972, as Lord Lisvane suggested the UK would have to do, it would still be incorporated in the devolved nations. As a result, it would be necessary to amend the relevant parts of devolution legislation to remove references to EU law, requiring consent from the devolved legislature, as Parliamentary convention dictates.

Furthermore, as the FT has reported, provisions in the Government of Wales Act, the Northern Ireland Act and the Scotland Act 1998 stipulate that acts not compatible with EU legislation are “not law”. In Scotland, control over agriculture and fisheries would default to Scotland as a devolved competence, as existing legislation reflects the assumption that these areas are the responsibility of the EU. Professor Douglas-Scott has suggested that such changes, requiring legislative consent, could lead to a “collision course” between Westminster and Holyrood.

Scotland – a second IndyRef?

Undoubtedly, one of the biggest questions would centre on whether the SNP use Brexit as an opportunity for a second Independence Referendum. The debate about Britain’s place in Europe has inevitably led to claims that Brexit could threaten the future integrity of the union, with First Minister Nicola Sturgeon warning it would “almost certainly” trigger a second referendum if Scotland's voters overwhelmingly elected to remain, whilst their English counterparts opted for Brexit.

In a report published by the House of Lords Committee on the Constitution, The Union and Devolution, peers warned that Brexit could threaten the future integrity of the Union if Britain voted to leave without majority support in each of the four nations.  

Scottish Conservative Leader Ruth Davidson echoed concerns in an article in the FT, in which she warned Brexit could “give oxygen to Scottish nationalists”. Meanwhile, rumours have surfaced about the potential for her own party to go its separate way from Westminster.

Following the Scottish Independence Referendum, Mr Davidson said, the “fundamentals of that union are strong, but we cannot ignore that this is a country still in a febrile, fragile state”. “A Remain vote”, she argued, “would help to put Britain’s debilitating constitutional uncertainty behind us”.


Over in Wales, the union with England is not likely to be terminated by Brexit, but Carwyn Jones and the newly re-elected Welsh Government will be keen to have their say over the UK Government’s next course of action.


Though a separate EU state, Brexit could alter the UK’s close relationship with Ireland. The Ireland Act 1949 stipulated that the Republic of Ireland was no longer a British dominion, but would not be regarded as a ‘foreign country’ for the purposes of British law. It has been argued that any future relationship between the UK and Ireland would be subject to agreement with the whole of the EU, not just between the two states. Withdrawal would also require the 1923 Common Travel Area, described as having “enormous symbolic and practical importance”, to be reviewed as it could lead to a “hard” border between Northern Ireland and the Republic.

In one of the more dramatic interventions of the campaign, former Prime Ministers Tony Blair and Sir John Major used their involvement in the Northern Ireland peace process in the 1990s to warn of the implications of establishing a “hard” border with Ireland. Furthermore, it has also been highlighted that the Good Friday Agreement of 1998 includes provisions from the European Court of Human Rights and the ECA.

On Monday, Taoiseach Enda Kenny made a passionate case in support of Britain remaining a member of the EU in the Guardian, noting the administrative burden and inevitable cost of leaving. He warned of the psychological effect of “a hardening border on the island”, highlighted the role of much-needed EU funding in Northern Ireland, and argued that Ireland was a co-guarantor of Northern Ireland.

From devolution statutes to peace processes, the uncertainty produced from Brexit could lead to a constitutional crisis across the UK. The procedural and practical consequences of withdrawal would have to be carefully balanced alongside the review of devolution settlements and the establishment of new relations.   

Jasmine Mitchell
Jasmine Mitchell
Political Analyst

Jasmine Mitchell is a Political Analyst at DeHavilland, where she monitors the UK Parliament and devolved institutions. She first joined DeHavilland as a Research Assistant in January 2015. Jasmine holds a BA in Modern History and Politics from the University of Liverpool and a Masters in Conflict, Security and Development from King's College London.