Combustion in hot, low oxygen environments, such as mild combustion is not well understood at pressure. To meet this gap in understanding, a confined-and-pressurised jet-in-hot-coflow (CP-JHC) burner has been developed to facilitate optical diagnostics of turbulent flames in hot and vitiated coflows for the studies of flame stabilisation, structure and soot formation at elevated pressures.The CP-JHC burner has been designed for steady operation at 10 bar(a) with internal temperatures of up to 1975 K with a water-cooled,4.6-mm central jet issuing into a hot oxidant stream produced by a non-premixed natural gas/H2 burner. This work describes the key features and operational capabilities of the CP-JHC burner and presents a selection of results from initial experiments. Temperature measurements of the hot coflow with heat inputs of 8.7-17 kW are used to estimate the enthalpy deficit of the stream, with thermal efficiency increasing with increasing heat input, and decreasing with increasing pressure. Preliminary mean and instantaneous images of turbulent natural gas/H2 and C2H4 flames, with and without chemiluminescence filters, are discussed in context of ignition pathways and soot formation at elevated pressures to highlight the need for future studies in this newly developed burner