This article explores the relationship between the 19th century ‘global transformation’ and the contemporary intensification of communication media through the lens of Greater Britain, a late-Victorian ordering imaginary centred on the integration of Britain and its white settler colonies. Contrary to existing conceptions of globe-spanning media as either components of ‘interaction capacity’ or boundary conditions that set broad outer limits for political thought, I advance an understanding of media as socio-technical and political structures in their own right and explore how they surface meanings and representations upon which imaginaries such as Greater Britain depended. The argument thereby contributes to IR debates on global modernity, communication media and the dynamics of historical change.