From the 1950s, aversion therapy gained an international foothold as a behaviourist means to alter what was then considered ‘deviant’ behaviour. Using primary research by psychologists, psychiatrists and other clinical figures published in professional journals, recently published personal testimonies by those who underwent such ‘treatment’, and drawing on the latest historical research, this article maps aversion therapy practices used to ‘treat’ LGBTQ+ people in the UK, mainly in the 1960s and 1970s. We outline our approach to this history and contextualise it by drawing attention to ongoing comparative issues of banning LGBT conversion therapy in the present. Next, we outline the emergence of aversion therapy internationally and identify historical ‘hotspot’ hospitals and universities in the UK, with the nation itself an international ‘hotspot’ for aversion. We then employ the case study of the 2022 report from the University of Birmingham, to demonstrate how such investigations of difficult pasts might be most effectively realised and highlight the potential for a ‘truth and reconciliation’ approach to this history. Finally, we call upon psy-organisations, university and research institutions, and other stakeholders to take this history seriously in effort to address past and ongoing harms enacted upon LGBTQ+ people.