Governments worldwide are paying increasing attention to the role of infrastructure systems in promoting economic growth and environmental sustainability. However, infrastructure planning and provision tend to be addressed in sector-specific silos which overlook the interdependencies between sectors and focuses upon the provision of projects rather than the performance of systems of systems. In this paper, we report on the development of the National Infrastructure System Model (NISMOD) family of models and, in particular, the NISMOD-LP model, which is a national model of the long-term performance of infrastructure systems. NISMOD-LP is driven by high-resolution demographic projects and regional multi-sectoral economic scenarios. These provide the basis for scenarios of future demand for infrastructure services. Separate modules simulate the future capacity and performance of energy, transport, water, waste water and solid waste sectors. These different perspectives are integrated through a common architecture for sampling uncertainties, construction of cross-sectoral policy responses and visualisation of future infrastructure performance.