This article considers the emergence of an informal institution vital to the functioning of Westminster polities: that the Shadow Cabinet is a 'government in waiting'. It compares the evidence for two theoretical accounts of its timing: a 'procedural' theory wherein the Shadow Cabinet is a solution to internal organizational issues in the House of Commons prior to widespread working-class voting, and a 'competition' theory that predicts that suffrage extension acts as a key stimulus for Shadow Cabinet organization. Gathering a dataset of almost a million utterances in parliament between the First and Fourth Reform Acts, the study provides a novel method of identifying Shadow Cabinet members using the surges in term use from their speeches. It finds that the 'competition' hypothesis is the most plausible version of events, and that the opposition responded to the new 'party-orientated electorate' by strategically reorganizing in a way that mimicked the cabinet's structure
