This paper presents the findings of research on potential strategies for the management of separated plutonium in the UK*. These strategies include the use of plutonium as a reactor fuel (MOX), or immobilising it as a waste. The paper reviews the hurdles to MOX fuel use in the UK. These include the need for large-scale subsidy for building new reactors. Estimates for the scale of the subsidy are presented. It also reviews the hurdles to immobilising plutonium using a ‘can-in-canister’ approach with vitrified High Level Waste (HLW), as originally proposed in the US. The paper discusses the requirements of alternative immobilization strategies. It identifies a range of options and presents cost estimates. The paper addresses the question of what would constitute a cost-effective approach to immobilization in a UK context.