Leaving the European Union: Stability of the United Kingdom’s Union

This House of Lords Library Briefing has been prepared in advance of the debate due to take place on 17 January 2019 in the House of Lords on the motion moved by Lord Lisvane (Crossbench), “that this House takes note of the possible effects of Brexit on the stability of the Union between the parts of the United Kingdom".

Concerns have been raised about the stability of the union since the 2014 Scottish independence referendum and the 2016 referendum on continued membership of the EU. In particular, the UK’s decision to leave the EU has given rise to constitutional questions about the future of relations between the UK’s devolved nations and the centre. These include how powers that currently reside at EU level will be exercised domestically after the UK’s withdrawal, and what mechanisms may be in place for inter-governmental communication and cooperation in the future. In addition, the asymmetric nature of the Northern Ireland backstop provisions in the UK-EU withdrawal agreement has potential implications for the union. Northern Irish unionists have argued that it threatens Northern Ireland’s place in the UK’s union. The Scottish Government has expressed dissatisfaction that the UK Government has not provided for Scotland to maintain a close relationship with the EU’s single market and customs union following the UK’s withdrawal from the EU, despite particular arrangements for Northern Ireland being contemplated under the backstop. Meanwhile, others have expressed concern that different arrangements for Northern Ireland could fuel support for Scottish independence.

Mechanisms proposed to address issues in the UK’s constitutional arrangements have included holding a constitutional convention to help build a consensus on a way forward, and a new Act of Union that could stabilise the framework in which the UK’s constituent parts could pool sovereignty.

This briefing provides background information on the union, before briefly examining issues that have arisen in debates on unionism since the 2016 EU referendum. It then provides an overview of recent proposals to stabilise the union, including a private member’s bill introduced by Lord Lisvane in October 2018 that is currently awaiting second reading. The briefing concludes with a selection of recommended further reading on the complex and multi-faceted issue of the future of the union in the context of the UK’s forthcoming withdrawal from the EU.