This article examines pro-European mobilisation in the UK following the EU referendum. It develops a framework that combines Isin’s ‘acts of citizenship’ with Nancy Fraser’s three dimensions of justice – redistribution, recognition and representation – to examine the way in which Brexit has served as a mobilisation trigger for claims about European citizenship. Drawing on data from a survey of participants of an anti-Brexit march in London, it argues that Brexit can be seen as a process that makes people aware of the ‘right to have rights’ as EU citizens. While some protesters experience Brexit as a struggle over the substance of justice within the UK, many of the ‘48%’ experience Brexit as a serious injustice that results from what Fraser calls ‘misframing’ in the context of struggles over the boundaries of the political community. In this sense, economic, cultural as well as political forms of injustice amount to a sense of personal grief over being ‘misframed’ in a UK outside the EU.