This article investigates the development of child analysis in Britain between the wars, as the anxious child succeeded the shell-shocked soldier as a focus of psychoanalytic enquiry. Historians of psychoanalysis tend to regard the Second World War as a key moment in the discovery of the ‘war within’ the child, but it was in the aftermath of the First War that the warring psyche of the child was observed and elaborated. The personal experience of war and its aftermath, and the attention given to regression in the treatment of war neuroses, encouraged Melanie Klein, Anna Freud and others to turn their attention to children. At the same time, however, the impact of the First World War as a traumatic event, with inter-generational consequences, remained largely unaccounted for within psychoanalysis as Klein and others focused on the child's riven internal world.