Using the Welsh Government’s Strategy for Older People as its example, this thesis aims to address questions arising from government encouragement, and sometimes insistence, on co-production in circumstances where the mechanisms are not defined and the legitimacy of any outcome is unchallenged. It seeks to find out what motivates older people to become involved in voluntary activity, considering why lay people may feel they have a legitimate right to speak or act for others, and why partnerships view them as legitimate representatives. Using network and power theories, it considers how and why people engage with or are missed from the mechanisms developed to engage them. The thesis starts with a review of academic literature and other knowledge sources. Following chapters address the challenges inherent in a research question which aims to consider the potential for co-production mechanisms to exclude, and give an outline of the policy context. The chapters on Motivation, Networking and Legitimacy illustrate contradictory claims of legitimacy, the importance of networking (rather than committee-based) skills, and the influence of clique membership and allegiance. The thesis concludes that in the example considered, power was unevenly balanced and this did govern and sometimes limit the approaches to co-production adopted, resulting in some people being excluded from the process entirely. However, it was not a simple imbalance of power between statutory organizations and older people. The approaches adopted, both very formal and less formal, attracted people who were motivated and suitably skilled to build their social networks. Consequently, whilst the research started by questioning whether existing approaches to co-production exclude, and so are not legitimate and lead to outcomes which are unjust, it ends by questioning whether concepts of legitimacy are just. This contribution to existing theories of legitimacy lead to questions which currently are not being addressed.