Keele Research Repository

The Wednesbury decision in 1947 was the beginning of a new era in public law in the UK, the Commonwealth and beyond. It established reasonableness as an independent ground of judicial review – and ever since has been the cause of on-going disputes, misconceptions and confusion. This paper focuses on UK and Australian public law, and describes how courts and public law scholars in these common law jurisdictions have been struggling to comprehend the meaning of ‘reasonableness’ as a head of judicial review in public law. The main purpose of this article is to promote conceptual clarity in UK and Australian public law by describing the nature of reasonableness as head of judicial review, highlighting the overlooked implications of applying reasonableness review, and clarifying the links between reasonableness review and other grounds of review. The main arguments of this article are that reasonableness is in its essence a balancing and weighing test; that this perception of reasonableness has overlooked implications both in UK and Australian public law; that perceiving reasonableness as a balancing and weighing test does not exclude all existing perceptions of reasonableness in UK and Australian public law; and that perceiving reasonableness as a balancing test shed a different light on the importance of the ground-breaking decision in Li in Australian public law. These arguments have general implications which are relevant to any legal system in which reasonableness is being used as an independent ground of judicial review.