The purpose of this dissertation is to address the question of how we can constitutionally justify the judicial review jurisdiction of the English courts. Two competing theories are commonly posited as providing this justification: the ultra vires theory and the common law theory. This research consists of a hermeneutical analysis of these two theories; it examines their rationales and the main themes of the debate between their supporters. It also uses immanent critique to reveal a significant lack of 'fit' between judicial review in practice and each of the theories. It is implicit within the two theories that they match the actual exercise of the supervisory jurisdiction. Thus, the lack of fit exposed by the critique brings into question any claims that either theory can provide the constitutional legitimacy for judicial review. The thesis advanced in this dissertation is in two parts. First, it is argued that the doctrine of parliamentary sovereignty operates as a principle. This means that legislation may be balanced against other principles derived from the common law or other statutes. This is in contrast to both the ultra vires and common law theories in which the doctrine is assumed to function as a rule. Second, under this novel conception of parliamentary sovereignty it is not necessary to justify the operation of judicial review by reference to legislative intent or express statutory provision. Rather, the standards of good administration may be rationalized as being developed and applied pursuant to an inherent jurisdiction of the courts.