Our objectives in the article are twofold. First, we draw on empirical evidence to extend debates around the problems and issues faced by teachers responsible for the delivery of counter-radicalisation measures in secondary educational contexts in the UK. Second, we identify persistent and demanding challenges for teachers arising from the mandatory incorporation of Prevent Duty Guidance into day-to-day professional practices. Drawing on a qualitative study, we use interview data to expose the ways in which educators both navigate their commitments and grapple with the quandaries that arise from carrying out safeguarding duties designed to counter radicalisation. Presenting data from teachers working in secondary educational contexts, we illuminate two key issues of concern: resource capacity and the prevalence of ‘safety-first’ decision-making in conditions of uncertainty.