This Working Paper is the first output of research on retail market governance in the theme on “Decision making”. Retail markets are the main commercial interface for most people with the energy system. Current retail energy market governance in the UK is characterized by a quite complex mix of arrangements that have evolved over time. The scale of governance is increasingly complex, for both technical and political reasons, with a trend towards multi-level governance. The role of EU institutions has increased and this seemed set to continue until the EU Referendum; some energy governance is now devolved (although to different extents in Scotland, Wales and Northern Irelandii); and some local government is beginning to play a more active role. However, the principal level is still the nation state, and that is therefore our predominant focus.