This study focuses on Private Finance Initiative (PFI) policy in the UK and specifically the relative policy inertia that has characterised the development of this procurement method. PFI is a contract between the public and private sector, where the private sector is responsible for the design, build, finance and operation of a public sector asset and associated services. UK PFI policy has persisted virtually unchanged in its structure for almost two decades, despite criticisms of the policy and a lack of evidence that it is effective and efficient. In order to explain this pattern this study explores the responses of the National Audit Office (NAG), Parliament and PFI private sector companies to the developments of UK PFI policy via a content analysis of relevant reports. In doing so, this dissertation is able to present PFI policymaking as a dynamic process in which different stakeholders (the NAO, Parliament and private sector companies) react to policy challenges and actively influence policy developments. Accordingly, it is noted that the private sector has not been a passive bystander in the PFI policymaking process but used assertive impression management techniques during periods of change in PFI use to gain and maintain legitimacy of PFI in public policy contexts; and thus was able to maintain favourable conditions for itself. The study also suggests that the NAO frequently commented on PFI in ways, which legitimised existing practice, whereas Parliament (particularly the Public Accounts Committee) was more critical of PFI and placed greater focus on potential taxpayer concerns. As an overall conclusion, this work suggests that the NAO, Parliament and private sector responses can help explain the continued political support for PFI and its relatively unchanged structure, which has been maintained despite criticisms and concerns regarding fundamental principles, such as value for money.