This paper investigates UK sovereign debt sustainability following the Second World War. While the UK in 1946 recorded the highest public debt-to-GDP ratio of the 20th century, the conventional view held by economists and historians is that the UK avoided a sovereign default following the Second World War. New archival evidence shows that Britain in fact ‘partially defaulted’ multiple times following the Second World War, and several British default instances can be further classified as ‘partially excusable’. The British case illustrates the challenge of identifying and accurately classifying sovereign credit events along with the complex dynamics of sovereign debt sustainability vis-à-vis other competing policy objectives, such as geopolitical priorities.