Combustion of hydrogen from renewable sources is an emerging technology that can replace fossil fuels and so provide carbon-neutral energy. The goal of POLKA is to solve serious technical problems, which are unique to hydrogen combustion: thermoacoustic instabilities and flashback. Thermoacoustic instabilities are large-amplitude pressure oscillations caused by an escalating interaction between the flame and acoustic waves; they tend to occur unexpectedly and cause major hardware damage. Flashback is the dangerous phenomenon of the flame propagating backwards into components not designed for high temperatures. The ultimate vision of POLKA is to create new physical insight and advanced simulation tools, so as to underpin the development of hydrogen-fuelled combustion systems (gas turbines, aero-engines, boilers furnaces, etc). The methods to be used are a combination of experiments, numerical simulations and analytical techniques. Experimental validation of numerical and analytical results is a high priority. POLKA will train a cohort of 15 ESRs, each enrolled in a 3-year doctoral programme. The research project is divided into 15 interlinked sub-projects, each forming an individual PhD project for an ESR. The ESRs will be equipped with a wide portfolio of skills, including traditional academic research, and also transferable skills in outreach and gender issues. This will be supplemented by a unique integrated training programme in innovation, exploitation and entrepreneurship. Secondments are an important part of the training programme. The ESRs will develop an innovation-oriented mind-set and have excellent career perspectives in the renewable energy sector. The POLKA website will feature an extensive range of open-access training resources, which will be maintained beyond the formal end of the project. POLKA has a balanced consortium, both in terms of gender (5 female and 6 male main supervisors), and in terms of sector (6 academic and 4 industrial beneficiaries)