This article explores a concept which is a substantive category of judicial review proceedings – ‘unreasonableness’. The ground received its name from the brilliant, landmark case of Associated Provincial Picture Houses Ltd v Wednesbury Corp  1 K.B. 223. This ground is also known as ‘irrationality’. As a result the following are used synonymously throughout the article: “Wednesbury Unreasonableness”, “Unreasonableness” and “Irrationality” (irrationality was a term coined in the case of Council of Civil Service Unions v Minister for the Civil Service  UKHL 9).
In 1947, Associated Provincial Picture Houses was granted a licenceby the Wednesbury Corporation to operate a cinema. This was on the condition that no children under 15, whether accompanied by an adult or not, were admitted on Sundays. Under the Cinematograph Act 1909 (current version not available online), cinemas could be open from Mondays to Saturdays but not on Sundays. The Sunday Entertainments Act 1932 (since repealed) legalised opening cinemas on Sundays, by the local licensing authorities, "subject to such conditions as the authority may think fit to impose.” This would be after a majority vote by the borough. Associated Provincial Picture Houses sought a declaration that Wednesbury's condition was unacceptable and outside the power of the Corporation to impose.
The main issue in Wednesburywas as follows: assuming that a public body has acted within the remit of its powers according to the statute that created those powers, were there any circumstances that allowed the court to intervene to quash a decision? The answer to this is a resounding ‘yes’. Within Lord Greene MR's part of the judgment (in particular at page 230), he confirmed that as well as scrutinising the procedure in making a decision, the court is also able to scrutinise the substance of a decision.
Generally, it is a well-established public law concept that a public body cannot act unreasonably in the performance of its public functions. The standard approach to Wednesbury unreasonableness is to show that a decision was so unreasonable that no reasonable decision-maker in the same position with the same facts could have arrived at the same conclusion.
The unreasonableness ground imposes a high threshold on an applicant of judicial review. The rule also forbids the court from substituting its own view for the view of a decision-maker. It can, however, be modified in certain circumstances. As a result, public bodies can be relatively well insulated from challenges on this ground alone. Generally, the ground of unreasonableness is successful in limited cases. It is likely the following cases would satisfy a finding of unreasonableness:
To blur the line further, the high threshold required for unreasonableness is merely a starting point. The concept can be applied flexibly, although this is dependant on the context. This is known as a ‘sliding scale’ and has been known to cause problems within the legal sphere; it requires some development to see where exactly the current case sits on the spectrum.
The best practical explanation of the sliding scale can be found in the decision of R. v Ministry of Defence Ex parte Smith  Q.B. 517, which concerned the policy that homosexuals could not serve in the armed forces. The Court of Appeal, whilst approaching the case on a Wednesbury basis, acknowledged the human rights dimension to this. It is important to note the Human Rights Act was not in force at this time, therefore reliance on the European Convention of Human Rights (ECHR) could only be done in the European Court of Human Rights. The Court of Appeal went on to state: "the more substantial the interference with human rights, the more the court will require by way of justification before it is satisfied that the decision is reasonable.” However, the Court of Appeal did not intervene in this case on the grounds that it was not for the court to make such a decision. Interestingly, Ex parte Smith was escalated to the European Court of Human Rights as: Smith and Grady v United Kingdom (1999) 29 EHRR 493 where the Claimants eventually won on the basis that there had been a flagrant breach of Article 8 ECHR rights.
Whilst one may immediately think that this is absurd, there are constitutional reasons as to why the bar to satisfying unreasonableness is so high. Practically speaking, should the threshold be too low, any court would be able to reverse any decision that it did not agree with. It follows that this could completely obliterate any form of the democratic process. It could also render any power instilled in public bodies futile. The consequences could see the judiciary shaping society through their own perception of the world, which is unacceptable on the basis that they are unelected.
Due to the above issue of the threshold being high, it is common to see the unreasonableness ground combined with other grounds, such as procedural impropriety or 'ultra vires' (acting beyond one's power - public bodies tend to receive their powers from legislative sources). A challenge on the grounds of unreasonableness is not normally on the decision-making process itself. One can appreciate that many judicial review claims are brought on the basis that there is some flaw with the decision-making process that has then skewed a decision which has been reached by a public body. However, it may be of assistance to the case and therefore necessary to illustrate whether a public body has acted irrationally by exploring how exactly the decision in question has been made.
Whilst the ground of unreasonableness does remain a complicated issue, it strikes an important balance between allowing some freedom to public authorities in order to make decisions that fall within their ambit, yet also protects citizens of the state. There is the additional advantage that a high threshold to satisfy unreasonableness curtails judicial activism. This particular branch of public law perfectly portrays the complex tripartite relationship between the state, its citizens and the judicial institutions that governs day-to-day life in modern society.