Well managed, maintained and effective national infrastructure (NI) systems (i.e. energy, transport, water, waste, ICT) provide the backbone for economic growth and societal wellbeing. Traditionally, NI planning and implementation has been conducted in isolation, based upon fixed assumptions about the future. This fails to recognise both the long-term socio-economic, climate-related and technological challenges and uncertainties of the coming century and the growing interconnectivity between these individual infrastructure systems. Here we develop a methodology for generating a range of strategies for the provision of NI suitable for an integrated ‘system-of-systems’ assessment of NI’s future management. To provide coherent links with policy choices, integrated strategies are developed at an aggregate level with a diversity of investment requirements, demand management techniques, and levels of environmental targets. To facilitate implementation within NI simulation models, the example strategies are constructed from sectoral sub-strategies focusing on changes in demand, capacity utilisation and capacity expansion. Further new strategies can be explored and the approach lends itself to an iterative analytical approach, potentially capturing a wide range of policy questions. It is illustrated using the future provision of Great Britain’s transport infrastructure as a case study, and demonstrates how cross-sector strategies for infrastructure provision can be developed.