A standard of unreasonableness used in assessing an application for judicial review of a public authority's decision. A reasoning or decision is Wednesbury unreasonable (or irrational) if it is so unreasonable that no reasonable person acting reasonably could have made it (Associated Provincial Picture Houses Ltd v Wednesbury Corporation (1948) 1 KB 223). The test is a different (and stricter) test than merely showing that the decision was unreasonable.