P.M.S. Blackett, Nobel Laureate in Physics in 1948, was a director of physics laboratories, a leader in the British Admiralty for wartime operational research, and an active voice in British science policy. This paper poses the questions of how Blackett came to be an effective and influential leader of research schools. How is the scientific leader's authority and influence established and perceived? Is there a role for charisma in definitions of scientific leadership, as suggested in some studies of research schools? What is specifically British in the character of Blackett's achievement?