This thesis draws upon three years spent evaluating the implementation of a Bail Support and Supervision Scheme in one local authority. It describes the development of the scheme within the locality, exploring its relation to the Youth Offending Team and youth court, and their associated liaison groups. In doing so I offer an exploration of theoretical considerations that explain how managerialist policies are translated into localised practice, from which a means to learn from and develop such policy will emerge. I develop a particular strand of activity theory, primarily from within the tradition established by Yrjö Engeström, and demonstrate its usefulness to the examination and understanding of nationally determined yet locally implemented social policies. Using the notions of object trajectory and expansive transformation, I show how local context has impacted upon the idealised object formation arising out of the managerialist policy aims. By exploring activity in the boundary zones between activity systems, I describe a series of material or transitory objects emerging in order to overcome the tensions and contradictions inherent in situated practice, culminating in a reinterpretation of the purpose of the scheme. I conclude by addressing the extent to which local context has altered the intent of the policy in implementation.