This paper explores relationships between ministers, special advisers and civil servants through the lens of a high-profile government crisis in Northern Ireland (NI). Although political–administrative relationships are a mainstay of public administration research, we still have limited understanding of how these relationships feature and function within the ‘Westminster family’ of governance when operating within devolved institutions or post-conflict societies, nor of their role in crisis. We use Scott’s institutional pillars as an analytical framework and conduct a documentary analysis of public inquiry witness statements to explore the Renewable Heat Incentive crisis which led to the collapse of the NI legislature. Utilising a novel application of existing theory, we demonstrate that the implementation of the devolved, consociational power-sharing model incubated new governance norms, that prioritised and legitimised the agendas and actions of political actors (ministers and special advisers), over civil servants. Specifically, in understanding how relational norms – particularly distrust – feed public policy failure and institutional crisis, our findings contribute to this research area and to the broader public administration field. Government institutional crisis negatively impacts upon public service delivery and the wider health of democracy. Understanding such crises is an important first step in their amelioration. Points for practitioners Structural, systemic and day-to-day behavioural layering of distrust adversely impacts government professionals’ ability to recognise, communicate and respond to risk; this can create policy problems, which can escalate, unchecked, until they have become full-blown crises. In order to proactively mitigate crises in other public policy contexts, managers and teams should build in awareness raising, reflection and management processes to individual and operational performance reviews to improve relational norms, and prevent the normalisation of distrust.