<p>The practice of political campaigning has evolved over time. Whilst once associated with public rallies and stirring political oratory, more recent campaigns are known for digital communication and targeted messaging. This article revisits the idea of campaign change by examining the idea of the datafication of campaigning. Exploring the dynamics of British party politics it asks why parties are using data, what specific types of data they are gathering and how these data are deployed in practice. Considering these questions, this article interrogates the organisational and democratic implications of campaign datafication. It argues that data have the capacity to change relations between citizens and political actors, creating new inequalities that affect the dynamics of British politics and have consequences for our understanding of electoral competition and democratic practice.</p>