Preclusive clauses, otherwise known as privative, exclusion, or ouster clauses, are statutory provisions which prima facie prohibit judicial review of the exercise of the discretionary powers to which they relate. As we shall see, such clauses take a variety of forms; all, however, raise the same fundamental tension between the rule of law (which strongly favors access to courts — and therefore judicial review) and the constitutional duty of the courts, under the doctrine of legislative supremacy, to give effect to the sovereign will of Parliament. Although never explicitly repudiating their loyalty to Parliament in this context, the courts pursue a clear policy of seeking to preserve judicial review in the face of preclusive provisions. This judicial attitude was recently exhibited by the Court of Appeal in R (Sivasubramaniam) v. Wandsworth County Court [2002] , which had no difficulty in rejecting a submission that a 54(4) of the Access to Justice Act 1999, which precludes appeal against certain decisions to grant or refuse permission to appeal, implicitly prevented judicial review of such decision.
