The debate about the International Holocaust Remembrance Alliance definition of antisemitism (IHRA) has generally focused on the meaning of the definition itself and the consequences of its adoption or non-adoption by institutions. Yet we know very little of how IHRA is applied in practice by institutions that adopt it. This article discusses the case of Professor David Miller of Bristol University, where the adoption of IHRA by the university did not prevent his absolution (subsequently overturned by the university) from accusations of antisemitism by one legal opinion that made reference to IHRA itself. This incident demonstrates the possibility that institutions might ‘subvert’ or simply neglect IHRA when dealing with accusations of antisemitism. This possibility is rarely mentioned by activist proponents and opponents of IHRA. There is therefore an urgent need for empirical research into the ways IHRA is understood and applied by institutions that have adopted it.