Abstract
For centuries, parliamentary privilege has stood as a bar against judicial review over the internal affairs of Parliament. The literature surrounding parliamentary privilege has mostly been about the scope of the privilege; few have discussed if the existence of the privilege itself is justified. This article undertakes that task, by examining parliamentary privilege as a defence against judicial review. Three propositions will be made. First, in the context of judicial review, parliamentary privilege is defined by the outer limits of the principle of exclusive cognisance. Article 9 of the Bill of Rights 1689 adds nothing. Second, parliamentary privilege as it relates to judicial review is incompatible with the two prevailing models of the separation of powers. Third, six arguments that may be made in favour of parliamentary privilege will be refuted. Accordingly, parliamentary privilege should no longer provide a defence towards judicial review.