CA-2024-002732 - [2025] EWCA Civ 958

The law governing when a decision-maker acts unlawfully by not taking a particular matter into account as part of the decision-making process is now well established. In R (Friends of the Earth Ltd and another) v Secretary of State for Transport [2020] UKSC 52, [2021] PTSR 190, the Supreme Court held:

“116.

As it transpired, very little divided the parties under this ground. The basic legal approach is agreed. A useful summation of the law was given by Simon Brown LJ in R v Somerset County Council, Ex p Fewings [1995] 1 WLR 1037, 1049, in which he identified three categories of consideration, as follows:

“the judge speaks of a ‘decision-maker who fails to take account of all and only those considerations material to his task’. It is important to bear in mind, however … that there are in fact three categories of consideration. First, those clearly (whether expressly or impliedly) identified by the statute as considerations to which regard must be had. Second, those clearly identified by the statute as considerations to which regard must not be had. Third, those to which the decision-maker may have regard if in his judgment and discretion he thinks it right to do so. There is, in short, a margin of appreciation within which the decision-maker may decide just what considerations should play a part in his reasoning process.”

117.

The three categories of consideration were identified by Cooke J in the New Zealand Court of Appeal in CREEDNZ Inc v Governor General [1981] NZLR 172, 183:

“What has to be emphasised is that it is only when the statute expressly or impliedly identifies considerations required to be taken into account by the [relevant public authority] as a matter of legal obligation that the court holds a decision invalid on the ground now invoked. It is not enough that a consideration is one that may properly be taken into account, nor even that it is one which many people, including the court itself, would have taken into account if they had to make the decision.”

Cooke J further explained at p 183 in relation to the third category of consideration that, notwithstanding the silence of the statute:

“there will be some matters so obviously material to a decision on a particular project that anything short of direct consideration of them by [the public authority] … would not be in accordance with the intention of the Act.”

119.

As the Court of Appeal correctly held in Baroness Cumberlege of Newick v Secretary of State for Communities and Local Government [2018] PTSR 2063 , paras 20–26, in line with these other authorities, the test whether a consideration falling within the third category is “so obviously material” that it must be taken into account is the familiar Wednesbury irrationality test ( Associated Provincial Picture Houses Ltd v Wednesbury Corpn [1948] 1 KB 223 ; Council of Civil Service Unions v Minister for the Civil Service [1985] AC 374 , 410–411, per Lord Diplock).

120.

It is possible to subdivide the third category of consideration into two types of case. First, a decision-maker may not advert at all to a particular consideration falling within that category. In such a case, unless the consideration is obviously material according to the Wednesbury irrationality test, the decision is not affected by any unlawfulness. Lord Bingham deals with such a case in Corner House Research at para 40. There is no obligation on a decision-maker to work through every consideration which might conceivably be regarded as potentially relevant to the decision they have to take and positively decide to discount it in the exercise of their discretion.

121.

Secondly, a decision-maker may in fact turn their mind to a particular consideration falling within the third category, but decide to give the consideration no weight. As we explain below, this is what happened in the present case. The question again is whether the decision-maker acts rationally in doing so. Lord Brown deals with a case of this sort in Hurst (see para 59). This shades into a cognate principle of public law, that in normal circumstances the weight to be given to a particular consideration is a matter for the decision-maker, and this includes that a decision-maker might (subject to the test of rationality) lawfully decide to give a consideration no weight: see, in the planning context, Tesco Stores Ltd v Secretary of State for the Environment [1995] 1 WLR 759, 780 (Lord Hoffmann).

As is clear from paragraph 120, the test for determining whether a consideration is so obviously material is the public law test of irrationality, that is, whether it would be irrational, and therefore unlawful, for the Secretary of State not to take it into account. It is not simply a question of whether a new consideration might realistically be capable of causing the public authority to reach a different conclusion, as suggested at paragraph 46 of the decision of Lane J. in R (Hayle Town Council) v Cornwall Council and others [2023] EWHC 389 (Admin), adopting an earlier formulation of the test by Sir Ross Cranston in R (Hardcastle) v Buckinghamshire Council [2022] EWHC 2905 (Admin), [2023] Env LR 462. Determining whether it was irrational not to take a particular matter into account will involve consideration of, amongst other things, the nature of the issue being decided, and the relevance and importance of the new material to that issue. The fact that a party to the appeal knew about the material consideration, but did not take steps to inform the decision-maker of it, is also likely to be a powerful indicator that the new material is not a material consideration . Put simply, it is not enough that the new matter might be capable of causing a decision-maker to reach a different conclusion. It must be a gamechanger.