This seminar will examine the United Kingdom’s shift in nuclear deterrent strategy in the early 1980s from population to leadership targeting—a change partly justified on ethical grounds and a prerequisite to the UK’s later acknowledgment that the Law of Armed Conflict applies to nuclear weapons. Drawing on the 1978 Duff-Mason report—a partially declassified government study evaluating alternative targeting options for deterring the Soviet Union—alongside additional archival sources and open-source data, we construct representative population and leadership target sets and estimate the resulting civilian fatalities using nuclear-weapon-effect simulation tools to assess differences in outcomes. Our findings indicate that UK strikes against Soviet leadership targets would have caused three to ten million civilian deaths—compared to 13 million from a population attack—and would have rendered large areas, including Moscow, uninhabitable for decades. Although UK officials claimed that counter-leadership targeting was ethical because civilians were not deliberate targets, the expected scale of civilian harm undermines this assertion. The historical record further reveals that such casualties were considered necessary for deterrence, casting doubt on the legality of leadership targeting. Extending our analysis to contemporary Russia using public data on the current UK arsenal confirms that these findings remain valid today.

Dr. Steve Fetter, Professor at the School of Public Policy at University of Maryland, College Park, in conversation with BRSL’s Dr. Cameron Tracy.