The long-standing debate about the power of the British prime minister has focused excessively on formal instruments of control exercised within Whitehall. By contrast, not enough attention has been paid to the ways in which prime ministers use rhetoric, formally and informally, to maintain themselves in power and to achieve their policy aims. The term ‘rhetorical premiership’ is used here to denote the collection of methods by which prime ministers since 1945 have used public speech to augment their formal powers. Set-piece oratory remained consistently important throughout the period, in spite of new technology and the rise of the sound-bite. However, parliamentary rhetoric underwent some important changes, and prime ministers spoke outside the Commons with increased frequency. Historians of the premiership should draw instruction from those scholars who have studied the rhetoric of US presidents, although caution must be exercised when drawing comparisons. Future study of the rhetorical premiership should involve close textual analysis of prime ministerial speeches, but this should not be at the expense of archival sources, from which important insights into the speech-making process can be gleaned.