There has been much written on industrial agglomeration, but it is Michael Porter’s cluster theory, above all others, which has come to dominate local and regional economic development policy. His work has been adopted by the OECD, EU, national and local governments the world over. He and his consultancy group have led reviews of national economic growth strategies in dozens of countries. This rise to prominence, however, is in the face of widespread critique from academics. Cluster theory’s theoretical foundations, its methodological approach and practical implementation have all been unpicked, leading some to label little more than a successful brand riding the wave of new regionalist fashions. Despite libraries of incredibly useful books and articles on clusters, there remains an absence of work which interrogates the translation of clusters into, and then through local and national policy. The aim of this article is to go some way to remedying the situation by examining the influence of Porter’s cluster theory charted through an examin- ation of UK regional development policy in the 1990s and 2000s. To help map the journey of clusters into and through UK economic development policy actor-network theory is adopted as an explanatory framework.