Recent ideational accounts of twentieth-century decolonization, one of the most important but least studied transformations in world politics, have highlighted the significance of mechanisms like principled beliefs and ethical arguments for explaining the triumph of norms and ideas like racial equality, human rights and self-determination and their role in ending colonialism. In this article, I engage with this body of literature and highlight, through a discussion of Britain and its reaction to Indian calls for self-determination from 1929 to 1935, that explanations that rely on the importance of the adoption and internalization of these norms and ideas by the colonizer and their subsequent extension to the colonized may miss certain critical elements at the heart of these colonial empires. Specifically, this article argues that metropolitan identities had a significant role in constraining and shaping the approaches of elite British policymakers when they were forced to respond to challenges to their colonial rule in India. Critically, this article also seeks to trace how change happens, by examining and discussing the processes, mechanisms and politics involved in the contestation of the dominant identity important to maintaining colonialism and the emergence of an alternative metropolitan identity.