This article tells the story of the birth of modern judicial review. In the conventional account, the judge-led development of judicial review is one of the great successes of the twentieth century common law: “the greatest achievement of my judicial lifetime”, as Lord Diplock famously put it. On this interpretation, from the mid-twentieth century onwards, the judiciary abandoned its earlier quiescence and, building on doctrines, approaches and remedies that had been used to control inferior tribunals since Victorian times, fashioned a new body of law capable of subordinating the administrative state to the rule of law. The modern law is thus seen as representing the same common law commitment to the rule of law seen in early cases such as Entick v Carrington and Cooper v Wandsworth. This article challenges this story of continuous unbroken development. On the face of it, the cases from Ridge to GCHQ did indeed draw on an older line of case law. Yet, as we demonstrate, the 1960s and 1970s were a transformative period in administrative law. Underlying the seeming doctrinal doctrinal continuity and consolidation, lay a deeper conceptual and theoretical discontinuity—a fundamental shift of approach from a ‘mediating’ conception of administrative law to a ‘public’ conception. While the motives underlying this shift were laudable, the resulting system of judicial review has nevertheless failed to achieve its objectives. We argue that the source of the problems lies in a system of judicial review designed to eschew questions of “merit”, and that truly addressing the problem will require us to revisit the issues which were at the forefront of debate in the first half of this century, but which have never received a satisfactory resolution