The doctrine of 'Wednesbury unreasonableness' in administrative law refers to a decision that:

The doctrine of Wednesbury unreasonableness originates from the English case of Associated Provincial Picture Houses Ltd. v. Wednesbury Corporation (1948), where Lord Greene MR held that a decision of a public authority can be challenged if it is so unreasonable that no reasonable authority, properly directing itself on the relevant law and acting reasonably, could ever have come to it. This sets a high threshold for judicial review-courts do not substitute their own view for that of the decision-maker but examine whether the decision falls outside the range of responses open to a reasonable decision-maker. The Indian Supreme Court adopted this principle in Tata Cellular v. Union of India (1994) for judicial review of administrative decisions. It is also termed 'irrationality' as a ground of judicial review alongside illegality and procedural impropriety.