This CoG will simultaneously address the outstanding research challenges to establishing the feasibility of large-scale photonic quantum computing by:1. designing, fabricating and optimising the required hardware (WP1) components—inc. waveguides, couplers, phase shifters, delays, interconnects, spectral filters, photon sources and detectors, and control electronics2. establishing paths to the integration (WP2) of these components into complete systems3. developing accurate, exhaustive and verified model of errors (WP3) in photonic quantum systems for optimised fault tolerance strategies, and efficient large-scale architectures (WP4)4. exploring and developing approaches to optimising this architecture both generally, and for specific applications (WP5)Addressing these challenges in parallel will be essential to realising the vision because interim outputs are required to address each challenge, and an iterative approach with the flexibility to redistribute resources and effort is necessary to reach an optimal solution in minimal time.