In this dissertation the opening up to competition of the ferry route between the cities Elsinore in Denmark and Helsingborg in Sweden is analysed. The Danish government was forced by a decision adopted by the Competition Directorate (DG IV) in the European Commission to open up this ferry route for ferry operators other than the state owned Danish operator, Danish Rail. Accordingly, the main case analysed in this dissertation illustrates the relationship between the competition authorities in the European Union (EU), empowered with supranational legislative powers through article 90 in the Treaty, and the member states. In the literature, DG IV, the service within the Commission mainly responsible for competition policy, is often described as an autonomous body. The main aim of this dissertation is to assess the autonomy of DG IV in its enforcement and implementation of EU competition policy; and, as the presentation of the main case above indicates, this question is discussed in the context of the introduction of EU competition policy into the domain of public sector monopolies. Two main broad approaches are adopted in analysing this area. First, a systems approach is set out, in which the EU competition policy-making regime is analysed by focusing on its development, legal foundation, and practical formulation in general and in relation to public sector monopolies. The aim here is primarily to reveal the nitty gritty of this regime, which till now has been only fragmentally described in the literature, and to ease the modelling of the main case study undertaken in this dissertation. The Elsinore case is then analysed by adopting three well known perspectives for analysing EU decision-making: an interest group approach; an interorganisational approach; and finally, an institutional approach. The analysis's main observation is that an institutional approach to EU decisionmaking seems to provide us with a more thorough understanding of the processes focused on here than the two other approaches, and that this, at least, should lead us to rephrase the notion of an autonomous DG IV in this area.