The Conservative Party is the oldest of the ‘mainstream’ British parties, but has only elected its leader since 1965. In this article, I explain the variety of methods used by the Party to select its leader and assess the impact of ‘democratisation’ over time. I begin by examining the informal ‘system’, known as the ‘magic circle’, which existed until 1965, and explain how and why it came to be abandoned. I then discuss the six elections between 1965 and 1997, when the Tory leader was chosen exclusively by the Party's MPs. Finally, I assess the impact of the ‘Hague rules’, according to which Party members have the final say, between their adoption in 1998 and the election of David Cameron in 2005.