This is the first thesis which offers a sustained study of working-class women who took part in the militant campaign for suffrage and remained loyal to the Pankhursts, not only during the campaign, but throughout their lives. Historians have often sought to demonstrate why working-class women would not be attracted to the Women's Social and Political Union (WSPU), identifying political and practical barriers to participation in militancy. The original historiographical contribution of this thesis is to reverse this question, asking instead why working-class women would be attracted to the WSPU, through a case study of the Kenney sisters. It identifies the factors that enabled their activism, the opportunities that activism created for them, and the benefits they derived from participating in this organisation. This starting point positions working-class women as significant actors and autonomous agents in the militant suffrage movement, rather than passive pawns subject to manipulation by middle-class women. In focusing on a particular family, it also begins to bridge the surprising lack of research on suffrage families, extending recent research on the historical significance of siblings into a new context. However, this thesis also makes a substantial contribution to modern British history as well as to histories of suffrage, feminism, women and gender. It uses the Kenneys' lived experiences to address questions of class and gender, politics and activism, and agency and identity in the early twentieth century. In doing so, it engages with broader historiographical themes including politicisation, networks and transnationalism. It is a history of education, literacy, religion, migration and social mobility as well as suffrage, and of teachers, theosophists, political activists, social reformers, friends and sisters as well as suffragettes.