The article contributes to debates about core executive capacity by analyzing the British and Japanese cases. First it examines the historical development, contemporary structures and current operations of the two cases. Then it compares their performance in five key areas: overseeing government policy in the domestic sphere; overseeing government policy in the external sphere; managing executive relations with the legislature; overseeing public finances; and managing public relations. It finds that the performance of the two systems is variable both internally across distinct areas of business and, to a lesser extent, comparatively across similar areas. Overall, however, the British core executive is shown to have considerably greater capacity for coordinating and managing policy flows through the system than the Japanese. Governing from the centre is more feasible in Britain than in Japan.