This article explores and explains escalating contradictions between two modes of clinical risk management which resisted hybridisation. Drawing on a Foucauldian perspective these two modes – ethics-orientated and rules-based – are firstly characterised in an original heuristic we develop to analyse clinical risk management systems. Some recent sociologically orientated accounting literature is introduced, exploring interactions between accountability and risk management regimes in corporate and organisational settings much of this literature suggests these systems are complementary or may easily form hybrids. This theoretical literature is then moved into the related domain of clinical risk management systems, which has been under-explored from this analytic perspective We note the rise of rules-based clinical risk management in UK mental health services as a distinct logic from ethics-orientated clinical self-regulation. Longitudinal case study data is presented, showing contradiction and escalating contest between ethics-orientated and rules-based systems in a high-commitment mental health setting, triggering a crisis and organisational closure. We explore theoretically why perverse contradictions emerge  rather than complementarity and hybridisation suggested by existing literature. Interactions between local conditions of strong ideological loading, high emotional and personal involvement, and rising rules-based risk management are seen as producing this contest and its dynamics of escalating and intractable conflict. The article contributes to the general literature on interactions between different risk management regimes, and reveals specific aspects arising in clinically based forms of risk management. It concludes by considering some strengths and weaknesses of this Foucauldian framing