As in Scotland, the majority of people (56%) in Northern Ireland voted to remain in the EU in the 2016 referendum. Given the fact that the Belfast/Good Friday Agreement 1998 (GFA 1998) was plainly based on the presumption of common membership of the EU, there are serious concerns about the impact of Brexit on the peace process. Although the EU-UK negotiations are in their early stages, the referendum result has already proved destabilising and it contributed to the collapse of the political institutions in January 2017.
The divisions apparent within the referendum result are a complicating factor. The vote was partially split along ethno-national lines: 85% of those who identified as ‘Catholics’ voted ‘Remain’ compared to 40% of those who identified as ‘Protestant’. The two major political parties (DUP and Sinn Féin) were also on opposite sides in this debate – although ‘liberal unionists’, including most of the UUP and the Alliance Party, were ‘Remain’ supporters (the UUP has since then ‘accepted’ the result of the referendum).
Leaving the EU will throw into sharp relief some of the political and social tensions hitherto mediated by EU membership. It has already re-opened the fractures concerning sovereignty in Northern Ireland and enlivened discussions on the possibility of a United Ireland across the island of Ireland. Brexit is clearly having an impact on the peace process.