A government administrator’s decision may be irrational because it does not take into account a vital material fact for making a rational decision in the light of the empowering legislation and its purpose. The relevant question for rationality is whether the means, including the process of making a decision, are linked to the purpose or
Where a court is asked to set aside legislation on the grounds that it breaches the principle of legality because the law is not rationally connected to the legitimate government purpose for which it is passed, the threshold is low. The connection must not be arbitrary but the law can be based on a reason
Courts will not lightly overturn decisions of administrators. This is judicial deference. But deference gives way to irrationality.
An irrational decision will be set aside, even if the court finds that it does not have the expertise to make the decision itself. In that case, the decision is remitted back to the decision-maker to decide