This study investigated the process of policy development and delivery in relation to the complex problem of health inequalities. The study examined whether Health Action Zones represented a new form of partnership that provided an effective mechanism for policy delivery. A schema of mechanisms for 'collaborative policy delivery' was constructed to provide the theoretical framework for evaluating the policy processes. It was contended that Health Action Zones could represent a practical demonstration and test of network management. The empirical investigation involved a comparative case study analysis of two HAZ and two non-HAZ areas in England. It relied on semi-structured interviews conducted over a period of three years and documentary evidence from all the sites. The development and changes in the health partnerships in the four areas were tracked between 1999 and 2002. Impact was assessed in terms of 'intermediate process outcomes' ie organisational changes and action that took forward strategies addressing health inequalities. The findings suggest that HAZ status helped accelerate growth in capacity for partnership working and the adoption of a more strategic approach to tackling health inequalities. HAZ case studies demonstrated distinct features of partnership working in comparison with the two non-HAZ case studies. HAZs systematically built leadership, management and institutional capabilities around the pursuit of health inequalities that involved organisational learning and development. Strategic progress and changes were more likely if the network building was an integral part of the mainstream processes through which players managed their inter-organisational relationships. The implications for network theory were considered. While network management has an important contribution to make to the policy process and policy delivery, it does not operate in isolation and has to be fostered and resourced. Network theory appears limited in dealing with contextual issues, particularly in coping with the political dynamics of the policy process. The importance of investment in developing the capacity of the network of players to engage in interagency working is not fully recognised. It is contended that more attention needs to be given to context, and to creating the conditions that promote network management and delivery of integrative strategies.