Harriet Dalrymple is Head of International Fusion and UK Fusion Energy Investment at the Department for Energy Security and Net Zero. She leads the UK’s international engagement on fusion, working with partners including the United States, Japan, Canada and Germany, and with organisations such as the International Atomic Energy Agency. She is also responsible for shaping strategy and investment for UK Fusion Energy Ltd., the delivery body for UK’s prototype fusion power plant STEP.

Previously, Harriet was Head of Electricity Market Reform Strategy, where she led a multidisciplinary team to develop key policy on electricity market design, managing complex interdependencies across the energy system. Harriet has extensive international experience, particularly in China, where she headed the Climate Change and Environment Network at the British Embassy in Beijing. She also served at HM Treasury, leading UK–China economic engagement. She holds degrees from Imperial College London and the University of Oxford.