The mobility of EU students and staff is threatened by Brexit, as the favourable conditions allowing for a frictionless cross-border academic learning and scientific research base are renegotiated at the highest political levels, including the pre-Brexit freedom of movement of persons and home fees for EU students. However, the UK higher education system is highly differentiated, and its hierarchical nature implies that criteria such as age, history, geographical location, economic resources, research activity, teaching quality, academic selectivity and socioeconomic student mix will have important ramifications when assessing the vulnerabilities of UK higher education institutions and the internationalisation of UK higher education should the UK leave the EU.