Most work in political science on class and political ideology is focussed on politicians’ class destination rather than class origins. Yet that is inconsistent with evidence in the case of the United Kingdom that the conditions of someone’s family upbringing do influence their politics. This article revisits the conceptualisation of class background in the current literature by redirecting attention to the sociological concept of class origin. We draw on in-depth interviews with 24 British Members of the Parliament to unpack how these political elites perceive their class background to have affected their political outlook and behaviour. Our results indicate that ‘class origin’ is more salient in the formation of Members of the Parliament’ political outlook than educational or occupational background. The manifestation of this political outlook is constrained, however, by party discipline. This tension in how British Members of the Parliament relate to their class origins has implications for how we think about the power of descriptive representation in politics.