Achieving the carbon target for steel and aluminium requires an industry-wide transformation which will result in new business models and new metal flows. The proposal aims to identify credible scenarios for achieving the target, to specify the barriers to achieving them, and to define the economic and policy measures required to drive change. In parallel, the proposal aims to deliver basic technology research that will allow more options for a future materially efficient steel and aluminium economy.It is widely agreed that a cut of at least 60% in global greenhouse gas emissions will be required by 2050 to limit the adverse effects of climate change. Steel and aluminium are responsible for 8% of global energy related emissions. Industry efforts to date have focused on reducing energy in primary production, and recycling metal by melting and re-casting. However, demand for both steel and aluminium is forecast to double, recycling rates are already around 60-70% and the most optimistic projections for energy efficiency improvements deliver only 30% reduction per unit output of material. Efficiency improvements alone are not sufficient, but the 2050 target can be achieved if, in addition to existing measures, energy used in converting ingots to products is halved, the volume of metal used in each application is reduced, and a substantial fraction of metal is re-used without melting. In pursuing this strategy, this proposal is aligned with the EPSRC strategic theme on energy demand reduction.The need for clarity about the physical implications of responding to the carbon target has become a major priority in the metal producing and using industry. Without the work described in this proposal, it is not possible for the government, industry and the public to understand and negotiate the choices they must collectively make in order to meet the carbon target in this sector. Accordingly, this proposal comes with support of 2 million in committed effort from 20 global companies, all with operations in the UK. The business activities of the consortium span primary metal production, conventional recycling, equipment manufacture, road transport, construction, aerospace, packaging and knowledge transfer.The work of the fellowship will be split between business analysis and technology innovation themes. The business analysis theme will identify future scenarios, barriers and a roadmap for meeting the target. This work will include specific analysis of future metal flows, application of a global economic model and the analysis of policy measures. The technology innovation theme aims to optimize the requirements for metal use through novel manufacturing process design, to increase material and energy efficiency in forming and finishing, and to develop solid-state closed-loop recycling for metals. Both themes will be developed in collaboration with the consortium, and will also draw on an international scientific panel and a cross-disciplinary advisory panel in Cambridge.The work will lead to two major reports for wide distribution, direct dissemination into the partner companies, training courses, technology assessments and physical demonstrations of the technology innovations. These will include a demonstration for public engagement. The results of the work on steel and aluminium will be used to stimulate interest among business leaders in other sectors, and will form the basis for a longer term Centre for Low Carbon Materials Processing in Cambridge.The Leadership Fellowship offers a unique and timely opportunity to undertake the basic research required to drive a step-change in material efficiency, by demonstrating that a different flow of metal through the global economy is technically and economically possible, and by inspiring and informing those who can influence change.