In Nagaenthran, the Court of Appeal reasoned in obiter that legislation ousting judicial review on grounds of illegality, irrationality, or procedural impropriety will ordinarily be unconstitutional. The precise logic employed here is unclear. Four interpretations have been offered, but they either do not reflect the court’s actual remarks, or complicate other aspects of administrative law doctrine. This article offers a fifth interpretation, which largely avoids these difficulties. Ouster clauses are ordinarily unconstitutional because they usually extend power-conferring provisions beyond the purposes Parliament intended them to serve.