LAUSR

Abstract Global economic governance outcomes in areas such as corporate taxation may be influenced by transnational policy communities acting at national and transnational levels. Yet, while transnational tax policy processes are increasingly analyzed through the politics of expertise, national preferences have usually been derived from domestic interest group preferences. We know little about how technical expertise interacts with interest group politics at national level, an important deficit given the sovereignty-preserving, decentralized way in which transnational tax norms become hard law. This article examines the drivers of expansion of the UK’s bilateral tax treaty network in the 1970s, which cannot be explained solely through monolithic interest group politics. Evidence from the British national archives demonstrates how tax experts in the civil service and the private sector, members of a transnational policy community, used tax treaties to impose OECD standards for taxing British firms on host countries, at times overruling the preferences of other political, bureaucratic and business actors. Expertise politics and business power may shape the development of norms and focal points within a transnational policy community, but it is often their interaction at domestic level that determines the implementation of transnational norms as hard law.