8. Substantive unlawfulness

This chapter shows that judges must substitute their own judgment for that of an administrative authority on some issues, in order to give effect to the principle of legality. When there is reason for non-deferential judicial review, deference would mean abandoning the rule of law. The more interventionist grounds on which judges will control the substance of some decisions—relevance, proportionality, and legitimate expectations—may involve little deference, depending on the type of decision and the context in which it is made. Each of these interventionist doctrines gives the judges the opportunity to do justice for a claimant and to improve public administration. For the very same reasons, each doctrine poses a danger that the judges will make themselves into surrogate administrators by overextending the grounds of judicial review.