The new expanded UK Consortium on Turbulent Reacting Flows (UKCTRF) will further utilise the developments of High-Performance Computing (HPC) to offer improved fundamental understanding and modelling of turbulent reacting flows, which are pivotal in the effective usage of energy resources, development of reliable fire safety measures, and manipulation of the combustion processes to ensure environmental friendliness. These challenges are multi-faceted, and will require collaboration across a wide range of scientific areas. The UKCTRF brings together 40 experts (PI, 6 Co-Investigators, and 33 members) across 19 UK institutions, experienced in using HPC to enable concerted collaborative Computational Fluid Dynamics (CFD)-related fundamental and applied research on turbulent reacting flows to reduce duplication, and tackle challenges grander than individual attempts. Since its inception in 2014, the UKCTRF has achieved significant scientific and industrial impact with over 400 journal and conference papers which utilised ARCHER. The President of the Combustion Institute, Prof. J.F. Driscoll, has stated in his support letter that the publications of the UKCTRF members are among the best which help develop the minds of young researchers and the support letter from Rolls Royce states that as a result of the UKCTRF significant progress was made in the prediction of combustion phenomena with the help of HPC. Over the next 4 years, the consortium's goals are to: (i) further utilise HPC resources to conduct world-leading turbulent reacting flow research involving Reynolds Averaged Navier-Stokes (RANS), Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS); (ii) extract fundamental physical insights from simulations to develop high-fidelity modelling methodologies to study turbulent reacting flows relevant to power production, transportation and fire safety engineering; and (iii) ensure a forward-looking software development strategy to develop computationally efficient algorithms, and effectively exploit current and future developments of HPC hardware. The proposed research will build on the foundations of the current UKCTRF (2014-2019) and Flagship Software development (EP/P022286/1) projects and will address universal challenges of energy efficiency, sustainability and high-fidelity fire safety. The progress in HPC will enable this new incarnation of UKCTRF to reinforce existing strengths, but also address the following timely intellectual and industry-driven challenges: (i) simulation and modelling of multi-phase reacting flows (e.g. droplet and pulverised coal/biomass combustion); (ii) combustion analysis of biogas and low calorific fuels derived from coal gasification; (iii) flame-wall interaction; and (iv) combustion at elevated pressures, which have only recently become accessible due to the advancement of HPC.