Walter Charles Marshall was born in Rumney, Wales, on 5 March 1932, the youngest of three children. He was educated at St. Illtyd’s College, Cardiff), and the University of Birmingham. He graduated with first class honours in 1952, and took his PhD two years later In 1954 he was recruited into the Theoretical Physics Division of the Atomic Energy Research Establishment (AERE) at Harwell, recently incorporated into the newly formed United Kingdom Atomic Energy Authority (UKAEA). Initially assigned to the Plasma Physics Group, Marshall soon returned to his interest in condensed matter physics, developing it further during two periods of study leave at the University of California, Berkeley (1957-1958), and Harvard (1958-1959). Upon his return to Harwell he became Leader of the Solid States Theory Group and, in 1960, Head of the Theoretical Physics Division. He subsequently spent sabbaticals at the Oak Ridge National Laboratory, Tennessee (1962-1963). The success of the Theoretical Physics Division shifted Marshall’s career onto a new trajectory, from pure science to the administration of applied science and technology. By the 1960s many of the scientific objectives that had led to the establishment of the Harwell laboratory in 1946 had been met and the future direction of the facility required new definition. He was promoted to Deputy-Director in 1966, to Director in 1968, and to Deputy-Chairman of the UKAEA in 1975. A concern that increasingly occupied Marshall in the wake of the oil crisis of the early 1970s was long-term energy supply. In 1974 he was appointed Chief Scientist to the Department of Energy, on a part-time basis, a remit he pursued in a variety of arenas. He chaired the Study Group investigating how combined heat and power (CHP) could be linked to district heating schemes, and he inaugurated the Energy Technology Support Unit (ETSU) at Harwell, which investigated energy options, encouraged energy conservation in industry and explored renewable sources of energy. But above all he became convinced that a growing nuclear component would be essential for a stable energy policy in the UK. This belief was not shared by the then Energy Secretary Tony Benn MP, and by 1977 Marshall was asked to return to his duties in the UKAEA full time. As the new Chairman of the UKAEA (1981), it fell to him to coordinate the work of a new Task Force to sort out disagreements over the design for a British Pressurised Water Reactor that complied with UK nuclear safety philosophies. The Task Force settled the design for Sizewell B. In 1982 he was appointed Chairman of the Central Electricity Generating Board (CEGB), and received a knighthood. His subsequent efforts to ‘keep the lights on’ during the 1984-85 Miners’ Strike helped earn him a peerage (1985). Much of Marshall’s time during his later years at the helm of the CEGB was taken up with repairing the image of nuclear power after the Chernobyl reactor accident in April 1986, and with advising the government on its plans to privatise the electricity supply industry. He wished to take the CEGB into the private sector in one piece and resigned in protest against the government’s decision in November 1989 to abandon plans for the privatisation of the nuclear industry. At the foundation of the World Association of Nuclear Operators (WANO) in May 1989, Marshall was elected Chairman of the Governing Board, a role he expanded following his resignation from the CEGB six months later. Among other things he used his two terms in office to set up a peer review system for nuclear operators and a Users Group for Soviet Built Reactors that would allow operators in the former Soviet Union to collaborate in a non-political way. After stepping down as Chairman of WANO in April 1993, he continued on as WANO Ambassador, advising the Users Group and lobbying the West for financial and technological aid to improve reactor safety in the countries of the former Soviet Union. From 1991 onwards he also became active in a new syndicate of Lloyd’s of London specialising in nuclear insurance, and he was co-opted as Western observer and participant (‘Overseas Advisor’) when a new think-tank-cum-laboratory, the Institute of Nuclear Safety (INSS), was set up by the Kansai Electric Power Company, Japan, in 1992. Marshall received numerous honours and awards during his life. These included honorary degrees from a number of British universities and both the Maxwell and the Glazebrook Medals of the Institute of Physics. He was elected a fellow of the Royal Society in 1971. He received a CBE in 1973, a knighthood in 1982 and was elevated to the peerage as Lord Marshall of Goring in 1985. He died on 20 February 1996.