With the need for the development of novel hydrogen-compatible combustion devices, physical understanding of the flame behaviour and the identification of thermoacoustic instabilities at relevant combustor operating conditions for hydrogen-air swirl flames will help speed up the development of hydrogen combustors, in line with the UK government's net-zero vision. The proposed research will offer potential benefits to industry and contribute to the progress of science in the areas of fluid dynamics, turbulence and net-zero combustion. These include (i) An advanced Direct Numerical Simulation (DNS) database for hydrogen-air premixed swirl flames under representative combustor operating conditions. (ii) A comprehensive understanding and a detailed analysis of the behaviour of the Precessing Vortex Core (PVC) under non-reacting and reacting flow conditions. (iii) Identification of the combustor operating conditions for which hydrodynamic/thermoacoustic instabilities exist. (iv) An in-depth analysis on extinction strain rates and heat release rate for lean hydrogen premixed flames. The outcomes of this project will offer knowledge on the flame stability limits and will contribute to the development of hydrogen based power generation and propulsion devices (e.g. gas turbines used for power generation and aircraft engines).