Theme: Government & Parliament | Content Type: Digested Read

Irish Unification After Brexit?

Patrick Diamond and Barry Colfer


Christian Holzinger

| 8 mins read

This year marks Northern Ireland’s twenty-five year anniversary of the 1998 Belfast/Good Friday Agreement (B/GFA), which brokered peace after years of conflict between two distinct ethno-cultural blocs: ‘nationalists’ and ‘unionists’. Yet even with this relative stability since 1998, the debate on whether Northern Ireland should become part of the ROI has been re-ignited in light of a Brexit referendum result in which a majority of citizens in NI voted to Remain. Alongside other favourable factors, such as Ireland’s strong economic performance and eroding unionist electoral dominance in recent elections, can we say that Northern Ireland may be inching closer to a border poll, and potentially re-unifying with Ireland?

In our judgement, this process is far from inevitable. Instead, we must consider the new political identities emerging in NI that will shape its future. Since the B/GFA, a new constituency of non-aligned voters has grown in size, typically supporting cross-community parties like the Alliance Party and the Greens, with multi-faceted social and political concerns. It is likely that those with ‘new’ identities will be unwilling to alter the constitutional status of NI if such a decision undermines the fragile accord established by the 1998 Agreement.

Furthermore, unionists remain hostile to re-unification, while there is support among a section of the electorate that traditionally identifies as ‘nationalist’ for remaining within the UK. And what about unification in practice? Integrating ROI and NI into a single polity would also mean uncomfortable compromises for voters in ROI. Where does this leave the possibility of Irish reunification after Brexit?

Tensions in identity and the impact of Brexit

Northern Ireland’s identities may be becoming more fluid, but tensions remain. The B/GFA aimed to reconcile identity differences by recognising both Irish and British citizenship for NI citizens. It acknowledged that national identity is chosen, not set by religious or ethnic bloodlines (traditionally protestants were associated with unionism; catholics with nationalism). However, the B/GFA in effect reinforced the unionist and nationalist divide since the purpose of the institutions it created was that ‘two communities’ in NI’s divided society could co-exist.

Without question, the ‘hard’ Brexit pursued by recent UK governments has served to bolster pro-Irish unity opinion in NI. It has inflamed political tensions and destabilised the B/GFA. For example, the NI Protocol and Trade and Co-operation Agreement (TCA) negotiated by the UK government and EU authorities avoids a hard border in the island of Ireland as NI effectively retains full access to the EU single market for goods and complies with their regime. Yet many unionists are vehemently opposed since it aligns NI’s economic and regulatory ties closer to the EU than to the rest of the UK (separated by a ‘border in the Irish Sea’). The UK polity is therefore destabilised.

It is suggested that a border poll followed by Irish unification is significantly more likely than it was before the 2016 referendum. Sinn Féin (the left-wing pro-unity party) has polled strongly in the ROI and came out on top in the 2022 Assembly elections in NI. Meanwhile, deteriorating relations between London and Dublin undermine the B/GFA and provide a further pretext for Irish unity.

The conduct of a border poll

What would unification look like if NI did choose a vote on its constitutional future? A border poll needs to be instigated by the Secretary of State for NI, and would almost certainly be accompanied by a vote in the ROI also. Two possible options are that NI could choose to join the ROI as one united Irish state, or it could become a sovereign Irish territory with the power-sharing institutions created under the B/GFA still intact.

The prospect of Irish unity has for generations captured the political imagination of many of those living in ROI. In 2020 Taoiseach Micheál Martin advocated a ‘shared island’ formula to promote closer cooperation with NI, committing €500 million to the initiative and pondering the current viability of reunification. Ireland's relative economic success since the 1990s has also redefined the terms of debate. Economic prosperity has unquestionably strengthened the cause of Irish unity. Irish GDP increased by 229 per cent from 1987 to 2007 as the country, fuelled by EU membership, transitioned from reliance on agriculture to hi-tech industries and global exports to become the ‘Celtic Tiger’ of Europe.

Voter opinion on Irish Unity

However, the NI Life and Times surveys conducted by Queen's University in Belfast show support for reunification consistently at around 20 per cent. The road to Irish unity is fraught with uncertainty: while support for the Union has declined in some quarters, there has been no significant increase in the number of NI voters who favour unification with the ROI since the 2016 referendum. This reflects the fact that unionist support has been historically stronger than nationalist support for unification.

What about the ROI? 54 per cent of voters support the ‘long-term goal of Irish unity’, but this support may be shallow: Irish citizens are overwhelmingly opposed to individual compromises that may be involved in unification (e.g. cuts in spending to provide additional support to NI and introducing a new flag). Indeed, unification is estimated to cost the ROI an estimated €13–14 billion per annum, as ROI taxpayers would be expected to support NI’s ailing post-industrial economy. Unsurprisingly, salient economic and social issues are likely to be as important as identity in any vote.

It may be that the current devolution settlement is still the ‘preferred form of governance’ in NI, with two-thirds believing that the B/GFA is still the ‘best basis’ for governing NI and wishing for more powers to be devolved down to the Assembly.


A border poll on Irish reunification, in the absence of effective dialogue and deliberative preparation, risks the spirit of the Good Friday Agreement and the peace that ended sectarian violence back in 1998. The traditional ‘nationalist’ and ‘unionist’ voting blocs it revolves around still persist, but are in transition: nationalism is confronting its relationship with a transformed Ireland, more prosperous and multicultural yet one where many ROI citizens have doubts about unification, even if they remain emotionally sympathetic. Unionism meanwhile revisits its attachment to Britain at a time of resurging English nationalism.

Above all, ‘new’ identities in NI have been taking shape since the B/GFA was signed. Those identifying as neither Catholic nor Protestant have risen from 6 to 17% since 1990, while such non-aligned voters are likely to determine the outcome of any finely-balanced vote on unification. Ethno-cultural status no longer wholly determines views on Irish unity. Voters see considerable potential in the current devolution settlement, and may view reforming and expanding the existing institutions as a less risky decision. Seen in that light, Irish unity is by no means an inevitable outcome, even if Brexit has thrown that binary choice into sharper focus.

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  • Patrick-Diamond_avatar.jpg

    Patrick Diamond

    Patrick Diamond is Senior Lecturer at Queen Mary, University of London.

    Articles by Patrick Diamond
  • Barry_Colfer_0.png

    Barry Colfer

    Barry Colfer is a Research Fellow at St Edmund's College and the Department of Politics and International Studies (POLIS) at the University of Cambridge.

    Articles by Barry Colfer