HOT: Hadal zones of our Overseas Territories is a multi-disciplinary program that will deliver a step-change in our understanding of the fundamental ecological and geological processes in the South Sandwich Trench (SST). The SST reaches water depths of around 8100m and uniquely is the only sub-zero hadal environment on Earth. This project will improve understanding of marine biodiversity and geodiversity to fill an identified knowledge gap supporting the existing Marine Protected Area and obligations under the Convention of Biological Diversity.