Proportionality, Unreasonableness and a Unified Model: Reframing the Spectrum of Intensity of Judicial Review

Abstract

One of the most contested issues in common law public law is the relationship between proportionality and reasonableness in judicial review. Neither the bifurcated model that draws a rigid line between the two standards nor the parallel mode that recognises both as general standards of review seems to be satisfactory, as courts always swing between these two standards resulting in legal uncertainty. This article attempts to suggest a unified model that is based on the jurisprudence of the CFA. First, it argues that as proportionality and reasonableness have overlapping elements, proportionality can replace reasonableness as a single standard of review by organising these elements within a more structured argumentation framework, which ultimately increases legal certainty. Second, this article highlights the similarities between Wednesbury unreasonableness and “manifestly without reasonable foundation”, which is a deferential standard for assessing proportionality. The similarities create an opportunity for Wednesbury unreasonableness being merged into unified proportionality and being part of the spectrum of intensity of proportionality review.