Questions of statutory interpretation form a significant portion of administrative law cases. Accordingly, judicial methodology in this area requires careful consideration by public law commentators. The core aim of this paper is to question the general orthodoxy that statutory interpretation is invariably a question for judges. In recent times, one prominent argument has been that between jurists arguing that interpretation should be the realisation of Parliament's intention (‘intentionalist’), and those who prefer the closely related but subtly distinct focus on its objective purpose (‘purposivist’). I contend that this argument, framed as a question over the inter-institutional relationship between Parliament and the courts, focuses on how interpretation is carried out without considering who is best placed to do the interpreting. Given, as I demonstrate with a series of case studies, that in hard cases the distinction between interpretation and discretion/policymaking can become obscure to the point of nullity, the debate fails to consider institutional arguments for judicial deference on questions of law. Moreover, and counterintuitively, the arguments of the intentionalists/purposivists can be used to bolster an argument for deference. My conclusion adopts a wider lens, setting out a broader constitutional argument for, and addressing objections against, cautious and context-sensitive deference.