This article investigates the self-presentation and the construction of immigration discourses in articles and policy documents published by the British National Party (BNP) and the UK Independence Party (UKIP). By combining corpus analysis with the Discourse-Historical Approach to Critical Discourse Analysis, a picture emerges of two parties whose use of language is governed by the same principle of differentiation. Fundamental to the BNP’s and UKIP’s language is the dichotomy in-group/out-group. The in-group analysis investigates the parties’ choice of form of self-representation, claims to unique competence, denial of attributes and mutual perception. The out-group analysis shows how the parties construct immigration, and focuses on the aspects of legal status, quantification and origin. The analyses suggest considerable lexical and conceptual similarities in both in-group and out-group formation.