This project is an opportunity to harness the synergy between world-leading scientists from four prestigious institutions to create the next generation modelling tools for complex multiphase flows. These flows are central to micro-fluidics, virtually every processing and manufacturing technology, oil-and-gas and nuclear applications, and biomedical applications such as lithotripsy and laser-surgery cavitation. The ability to predict the behaviour of multiphase flows reliably will address a major challenge of tremendous economic, scientific, and societal benefit to the UK. The Programme will achieve this goal by developing a single modelling framework that establishes, for the first time, a transparent linkage between input (models and/or data) and prediction; this will allow systematic error-source identification, and, therefore, directed, optimal, model-driven experimentation, to maximise prediction accuracy. The framework will also feature optimal selection of massively-parallelisable numerical methods, capable of running efficiently on 10^5-10^6 core supercomputers, optimally-adaptive, three-dimensional resolution, and the most sophisticated multi-scale physical models. This framework will offer unprecedented resolution of multi-scale, multiphase phenomena, minimising the reliance on correlations and empiricism. The investigators' synergy, and their long-standing industrial collaborations, will ensure that this Programme will result in a paradigm-shift in multiphase flow research worldwide. We will demonstrate our capabilities in two areas of strategic importance to the UK: by providing insights into novel manufacturing processes, and reliable prediction of multiphase flow regime transitions in the oil-and-gas industry. Our framework will be sufficiently general to address a number of other industrial and environmental global challenges, which we detail herein.