This paper analyses implementation of the 1991 Urban Waste Water Treatment Directive (UWWTD) in England and Wales. In its Fifth Environmental Action Programme (5th EAP, 1993-2000), the European Commission committed itself to improving the implementation of EU environmental policies. It has been suggested that implementation will be more effective when the fit between Directive imperative and member state administrative tradition is close. Unfortunately, the fit approach sheds little light on the processes by which an accommodation is reached between Directive and member state. The approach to UWWTD implementation taken in England and Wales has recently shifted, changing from a minimalist approach to a more precautionary approach. This change affords a useful opportunity to analyse the processes by which member states and Directive requirements mutually adjust during implementation. In this case, these processes are explained by broadening the analytical sweep to include the machinations of relevant member state policy networks and the influence of outsider policy beliefs that orbit those networks.