In relation to peace and security, many commentators have speculated as to the impact that leaving the EU could have on the future of peace and security in Northern Ireland. For some, the implications include a danger of the peace process unravelling, the cessation of cross-border peace programmes and a return to the ‘hard’ border that featured so prominently during the Troubles. This includes former Deputy First Minister of Northern Ireland, Martin McGuinness, who has warned that leaving the European Union could “undermine all-Ireland bodies and co-operation created by the peace process and it will harden partition. It will have consequences for human rights legislation which, again, is specifically referred to in the Belfast and subsequent agreements”. In addition, during the passage of the European Union (Notification of Withdrawal) Bill in both Houses, concerns were raised regarding the impact that leaving the EU would have on the peace process. This included a number of amendments that sought to take account of the Good Friday Agreement when triggering Article 50 and ensuring that borders between the UK and Ireland remained open once the UK formally withdraws from the EU. In contrast, others have suggested that there will be little or no impact on the peace process, such as the UK Prime Minister, Theresa May, and former First Minister of Northern Ireland, Arlene Foster, who have both stated on multiple occasions that they did not want to see a “return to the border of the past”, reminiscent of the border arrangements during the Troubles.
In terms of trade, should the UK withdraw from the EU, it could possibly impact on bilateral trade relations between the UK and Ireland. As of 2015, the value of trade in exports to Ireland from the UK was £15.1 billion, whilst the value of trade in imports from Ireland to the UK was £11.2 billion. The Economic and Social Research Institute think tank “suggest that a Brexit is likely to significantly reduce bilateral trade flows between Ireland and the UK” and that “the impact could be 20 percent or more”. Others, such as Arlene Foster, have argued against the UK staying in the EU for the sake of existing trade agreements. Writing an article for the Guardian, Foster contended that “there is no evidence to support the case that either Scotland or Northern Ireland should stay in the EU ‘for the sake of’ trade with the rest of the EU”.