Education is usually considered a force for good, associated with hope and optimism about better individual and social futures. Yet a case can be made that education and education policy in recent decades, far from being a force for good, has had nefarious effects at multiple levels. This can be seen in the growing alienation of significant numbers of teachers and students in disparate global contexts and in the growth of authoritarian models of schooling, involving 'zero-tolerance', 'no excuses' disciplinary approaches, that have undermined notions of the common school as a public good. Against this background, and drawing on philosophical literature and our own empirical research, this study interrogates the practice in schools in England of placing students in 'isolation'. In considering this practice as an instance of banal education policy, our study makes obvious reference to Hannah Arendt's characterization of evil in her account of Adolf Eichmann's trial. But it also draws on the work of moral philosophers, Elizabeth Minnich and Simona Forti, in relation to the distinction between intensive and extensive evil, in order to analyse the nature and effects of school discipline policies and practices such as isolation in the neoliberal era as a contemporary form of evil.