This article presents a new database on U.S. multinationals active in British manufacturing between 1907 and 1962. Britain was the largest European host economy for U.S. direct investment in manufacturing and the second largest host worldwide. This article identifies the industrial distribution and mode of entry of U.S. investors, and offers explanations for the time trends which are shown. It goes on to trace the evolution of U.S. subsidiaries, and shows that rates of divestment were substantial. An examination of the characteristics of U.S. subsidiaries, including the substantial investments in R & D and high export propensity, is followed by a survey of British public policy, which made Britain an attractive host but did little to shape the form of U.S. investment.