This proposal concerns the debris discs of nearby stars; ie, discs of asteroids, comets and dust. Such dust can be imaged, providing clues to the underlying planetary system. Debris images have already predicted planets later confirmed in direct imaging. Most debris lies in cold outer (~100AU) regions of planetary systems, but a growing number of stars have hot dust in regions where terrestrial planets are expected (few AU). This proposal aims learn about the planetary systems of nearby stars through study of their debris discs. Specific focus is on the frontier area of characterisation and modelling of dust within planetary systems, which is important for the design of missions to detect habitable planets, a high priority goal for the next decade. The PI has played a significant role in debris disc studies, and proposes to consolidate an independent research team in Cambridge. The proposal covers 3 studies supported by 3 PDRAs. Specific objectives are: 1) Debris disc observations: Carry out survey for cold debris around unbiased sample of nearest 500 stars with Herschel and SCUBA2. Follow-up bright discs with high resolution imaging using ALMA and JWST to characterise sub-structure from planets and search for dust at multiple radii. Pioneer survey for hot dust using polarisation and interferometry. 2) Debris disc modelling: Develop new model to follow the interplay between collisions, radiation pressure, P-R drag, sublimation, disintegration, and dynamical interactions with planets. Use model to consider nature of small particle halos, resonant ring structures formed by terrestrial planets, and level of cometary dust scattered into inner regions. 3) Debris disc origin: Demonstrate constraints placed on planet formation models through studies of dust from Earth-moon forming impacts, effect of planetesimals on late-stage planetary dynamics, population synthesis explaining planets and debris, constraints on primordial size and stirring of debris.