The impact of Brexit upon the protection of social rights has received comparatively little attention, both in the public media and the academic literature. Social progress achieved on the island of Ireland since the conclusion of the Good Friday/Belfast Agreement can be seen as a product of that Agreement and Irish and British European Union (EU) membership – the former has generated the stability necessary for citizens to enjoy the opportunities and protection afforded by the latter. Brexit has put this social progress at risk and has already led to rights backsliding in social contexts. However, the mechanism created by the Protocol on Ireland and Northern Ireland to address diminutions of rights flowing from Brexit – article 2(1) – is not, we contend, suitable for preventing diminutions in social rights. We demonstrate in this article that the test for breach of article 2(1) focuses on specific breaches of individual rights and therefore does not cover situations in which regression in rights protection cannot be tied empirically to individual circumstances. The enjoyment of social rights on the island of Ireland is often facilitated by horizontally applicable EU law, and changes in levels of protection of social rights are often best observed at the population level over time. Using several case studies, we demonstrate how social rights backsliding on the island of Ireland that is attributable wholly or mainly to Brexit likely cannot be litigated through the application of article 2(1) of the Protocol, and we reflect upon the inadequacy of this situation.