ABSTRACT
This chapter explains the concept of 'ultra vires' and discusses the constitutional basis for judicial review and arguments against ultra vires as the basis for review. It outlines the concepts of illegality, irrationality and procedural impropriety. The ultra vires principle is consistent with the doctrine of parliamentary sovereignty and, to some extent, with the concept of the rule of law. However, there are objections to the courts holding so tenaciously to a concept which, in some respects, is inappropriate to describe what the courts actually do in the control of administrative powers. Judicial review on human rights grounds is a fertile and rapidly expanding area of the law. Here the courts are increasingly adopting the concept of proportionality to evaluate the legality of administrative action although there is no consensus on whether proportionality as a ground for review has expanded beyond the realms of human rights and EU law and entered into the broader areas of domestic public law.
