The authors discuss their application of John W. Kingdon's multiple streams framework (MSF) and the role it plays in the analysis of a pioneering local public policy in the United Kingdom (UK). The aim of this policy, instituted in 2009 and initiated by a group of Bristol's mothers, was to reclaim children's right to play, mainly for their own enjoyment and sense of freedom and independence but also for all the important functional, healthy, and developmental outcomes of free outdoor active play. Their play street model was disseminated to more than one hundred other local authorities within a decade and obtained the explicit support of the UK government. The authors intend their analysis and conclusions both to contribute to the MSF and policy change literature and offer lessons learned in Bristol as useful for children's right to play advocates, social movements, policy makers, and strategic planners.