On 29th March 2019, the last day for the UK’s planned departure from the EU and the date the Brexit withdrawal agreement should have come into force, the BBC, in a charming example of British understatement, described Brexit as ‘an enormous distraction’. Traditional rational economists may be baffled by the UK’s apparently irrational actions. From a behavioural perspective, however, the Brexit process displays classic characteristics of psychological bias and emotional decision-making overriding rational choice. After three years and three prime ministers, Brixit remains as contentious, divisive and intractable as ever. Driven by populist politics, the fear, held by a significant percentage of voters, that their frustrations can be resolved through isolation, whether by building a wall or trade wars, has taken centre stage on both sides of the Atlantic.