This thesis explores the following research question: what factors explain the relationship between levels of government over the implementation of European Union regional policy? Debates in political science and economics in the late 1980s and early 1990s considered whether a Europe of the Regions provided a model for the future economic and political order of Europe. Although these debates informed our understanding of European Union policy making, they have now moved on. The theoretical framework for this thesis tests the extent to which European integration can be explained by processes of multi-level governance, and not by the previously dominant systems of intergovernmentalism. Furthermore, much of the previous theoretical work on European integration has drawn from the earlier stages of policy making (on budgetary decisions, and on institutional and regulatory design). This thesis considers instead the neglected area of the implementation of the Structural Funds in two regions (Yorkshire and Humberside, and Lorraine). Using policy networks tools of analysis it tests the explanatory capability of multi-level governance in the following areas: the variation in policy implementation between the United Kingdom and France; the patterns of resource mobilisation in policy implementation; and the formation of regional economic strategies. The main findings of this thesis show that where domestic regional policy frameworks are weak (e.g. in the United Kingdom), the European Commission has been able to effectively mobilise resources at critical phases of policy implementation - such as during the negotiation of economic strategies. However, over the longer term, the direction the Structural Funds have taken is driven by actors and institutions outside those directly involved in the implementation of the Structural Funds. That is, both DG XVI of the European Commission and the regions themselves have limited opportunities to influence the course of European political integration.