This briefing first gives an overview of the differing definitions and understandings of the term ‘circular economy,’ revealing how many of them fail to consider the resource use and externalities across the full plastics life cycle and supply chain, focusing rather disproportionately on waste management and disposal. The briefing then outlines key principles on which a circular economy framework must be built, including considerations along the full plastics life cycle, from resource extraction, production, manufacture, transport, and consumption, through to disposal, leakage, and contamination of flora and fauna, including human bodies.