The phenomenon of Brexit is reordering British politics. Its effects have led to political and cultural shock, disruption and rifts. This article explores how the phenomenon of Brexit has decentered the Labour Party’s ideational traditions. The article utilises a mixed methodology which combines qualitative and quantitative data in the form of scholarly literature on Labour history, Labour Party manifestoes, speeches and media interviews by front-line politicians as well as polling data. In particular, the article analyses how Labour politicians are reimagining the two main traditions of thought: the euro-enthusiast tradition and the euro-sceptic tradition. The article argues that Labour’s euro-enthusiasts are reimagining the tradition as a full blooded cosmopolitanism and this is simultaneously controversial and high risk because it has refashioned Labour’s interests into a narrower social and cultural electoral offering.