The human population faces multiple economic, social and environmental challenges as the global population increases along with the demand for a resource-intensive lifestyle. Population growth over the past century has been driven by advances in medicine and associated reductions in child mortality. With this has come increased pressure on productive lands to grow food, yield resources and, most recently, generate energy.¹  It is recognised that the current global model of linear consumption is unsustainable (Chapter 1).²  This is driving a transition to models for utilising materials in a more circular manner: maximising the value obtained from resources and minimising waste at all stages of a product or service lifetime.³  This should be accompanied by reductions in primary resource use in order to achieve important social and environmental benefits.^2,4  A more circular approach is being implemented within the business sector (e.g. the development of standards to guide the design of circular business models⁵ ) and within policy via the ‘EU Circular Economy strategy.’⁶