["JCMS: Journal of Common Market Studies, EarlyView. ", "\nAbstract\nWhy has the United Kingdom repeatedly restored substantive compatibility with European Union (EU) regulatory norms despite formal withdrawal? This article introduces the concept of asymmetric regulatory embeddedness (ARE) to explain post‐membership governance in highly integrated sectors. ARE captures the structural condition in which a former member state remains economically, institutionally and infrastructurally embedded within a dominant regulatory ecosystem, resulting in bounded autonomy after legal exit. The article theorises adaptive convergence as the mechanism through which divergence initiatives confront embeddedness‐induced constraints and are incrementally recalibrated. Drawing on process tracing and discourse analysis of UK Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) and sanitary and phytosanitary/pesticide governance (2019–2025), the study shows how market interdependence, epistemic infrastructure dependence, institutional path dependence and legitimacy pressures produce functional compatibility without formal obligation. The findings extend Europeanisation beyond hierarchical membership, conceptualising EU influence as structural and relational rather than coercive. It provides a dynamic framework for analysing regulatory governance under conditions of post‐membership interdependence."]