In this article we explore the prescriptive approach to language use in its relation to ideology, past and present. Before Saussure, prescriptivists formulated rules from an instrumental perspective, which saw formal language as a means to persuade, partly by borrowing authority from august sources. We can now see this view as an ideology, and by analysing the mental components of ideology further we argue that the modern prescriptive approach to language appeals to a hierarchical view of society, and hence of language. This view is in conflict with the more recent ideology of equality, and contemporary processes of standardisation need to be understood by reference to this conflict. We argue at the same time that modern ‘descriptive’ linguistics, by taking the standard as its model, risks contamination from prescriptivism