As is well known, the group “Palestine Action” has been subject to proscription by the Home Secretary under the Terrorism Act 2000. The Court of Appeal has recently handed down judgment in litigation challenging the designation: Secretary of State for the Home Department v R (Huda Ammori) [2026] EWCA Civ 721. The Divisional Court had found the proscription of Palestine Action to be unlawful. The Court of Appeal has reversed the Divisional Court’s decision, and therefore reinstated the decision of the Home Secretary. Subject to any decision of the Supreme Court, Palestine Action remains a proscribed terrorist organisation.

The decision whether to proscribe Palestine Action is highly controversial. I do not seek here to get into the merits of the proscription decision: there may be powerful arguments either way. Indeed, this post is concerned with only one of the grounds of the Court of Appeal’s decision: specifically whether the Divisional Court was correct to find the Secretary of State had misinterpreted her own policy in relation to the proscription of organisations under the 2000 Act. The Divisional Court’s approach to the interpretation of policy has been subject to a considerable amount of discussion: mostly critical by Gabriel Tan, Dane Luo and Gabriel Tan, and Mark Elliott; Daniella Lock provided a defence of the Divisional Court’s decision in this regard.

The general context of this litigation will already be familiar to readers of this Blog, and therefore this post will give only a brief outline of the case. It starts with the Secretary of State’s powers and policy, before setting out the reasoning of the Divisional Court, and the Court of Appeal, in relation to policy. In terms of assessing the correctness of the Court of Appeal’s decision, what this post will seek to do is to apply a framework for the identification of the objective interpretation of administrative policy, which I have previously developed. In short, this approach involves identifying the legitimate audience of a policy document, and then seeking to ascertain how the least expert member of that audience would have understood the policy. My view is that the Court of Appeal’s decision appears more consistent with this methodology than that of the Divisional Court.

The Legislation and the Policy

The Terrorism Act 2000 provides that the Secretary of State may proscribe an organisation as a terrorist organisation if she believes it to be concerned in terrorism (s 3(4)). In broad-brush terms, it is an offence to belong or profess to belong to a proscribed organisation (s 11), to invite support for such an organisation (s 12), or to wear or publish an image of clothing or an article so as “to arouse reasonable suspicion that he is a member or supporter” of such an organisation (s 13).

The Home Secretary’s power to proscribe an organisation is discretionary. How she will exercise this discretion is the subject of Policy. This includes:

“What determines whether proscription is proportionate?

If the statutory test is met, the Home Secretary will consider whether to exercise their discretion to proscribe the organisation. In considering whether to exercise this discretion, the Home Secretary will take into account other factors, including:

• the nature and scale of an organisation’s activities
• the specific threat that it poses to the UK
• the specific threat that it poses to British nationals overseas
• the extent of the organisation’s presence in the UK
• the need to support other members of the international community in the global fight against terrorism.”

The Divisional Court’s Decision Regarding the Policy

The Divisional Court held that the meaning of “proportionate” in the policy did not mean the same as the legal test to be applied by a court, as set out by the Supreme Court in Bank Mellat v HM Treasury (No 2) [2013] UKSC 39, [20]. It would be odd, said the Divisional Court, were the Policy just to require the Home Secretary to decide on the same basis as would a court [79]. Instead, the meaning of proportionality in the Policy required a comprehensive exercise of the Secretary of State’s discretion [80]. Nevertheless, the difference between these approaches would not have affected the Divisional Court’s decision [81]. Further, the Divisional Court held that the word “activities” in the Policy did not mean all of the organisation’s activities, but rather only the activities which would constitute terrorism under the 2000 Act [82].

The real problem with the Home Secretary’s decision, according to the Divisional Court, was in the approach to “other factors”. The meaning of “other factors” must be consistent with the purpose of the policy. The Divisional Court determined, on the basis of those factors which were specified in the Policy, that the purpose of the Policy must be to restrict the Home Secretary’s power to proscribe. Not all organisations meeting the legislative test would be proscribed [89]-[92]. “[W]hether generic, or specific to the organisation under consideration, the factor must contribute to explain the particular need to proscribe that organisation above and beyond the necessary belief that the organisation is one that is concerned in terrorism” [91]. The “operational consequences” of a decision to proscribe an organisation were not factors which fell within the scope of the Policy, unless “the consequences of proscription would be unusually effective” [94].

The Court of Appeal’s Decision

The Court of Appeal, in one of the most powerful constitutions of modern times (the Lady Chief Justice, the Master of the Rolls, Edis LJ (the Vice President of the Court of Appeal (Criminal Division)) and Lewis and Whipple LJJ) disagreed with the Divisional Court’s approach. The Court of Appeal found the Divisional Court’s approach to the Policy to be “excessively analytical” [88].

The reference to proportionality in the Policy was to the Bank Mellat approach: there was nothing wrong with a policy setting a standard which could also be applied by a court on review [78]. Further, “activities” in the Policy was not limited to those which would be terrorism within the meaning of the legislation [89].

As to the approach to interpretation, the court stated that policies are not statutes, and this forms part of the context for their interpretation [80]. Turning to the relevant text of the Policy, this is “brief, unsophisticated and open-textured in its language” [82]. Given how important was the purpose of the Policy according to the Divisional Court, the Court of Appeal’s view of the purpose was key. As to this, the Court of Appeal held [83]:

“The Home Secretary contends that the purpose of the Proscription Policy was to render transparent some of the non-exhaustive factors that will be considered. We agree. There is nothing in the wording of the Proscription Policy, which is broadly framed, to indicate that its purpose is to limit or constrain the factors to be considered.” [83].

Even if the purpose of the Policy was to cut down the scope of discretion, this would not have meant that operational factors would have to be ignored, since operational factors could, in appropriate cases, weigh against proscription [84]-[87]. The Secretary of State could take into account operational benefits, and her interpretation of the Policy was not flawed [88]-[90].

Evaluation of the Court of Appeal’s Decision: The Eyes of the Audience

It is well-established that the correct interpretation of administrative policy is a matter of law, on which the courts have the final say: Tesco Stores Ltd v Dundee CC [2012] UKSC 13. However, the courts have been anxious to make sure that this interpretative function does not lead to judges overstepping their proper role. The Supreme Court has therefore discouraged overwrought interpretations of policy: Hopkins Homes Ltd v Secretary of State for Communities and Local Government [2017] UKSC 37; Samuel Smith Old Brewery (Tadcaster) v North Yorkshire Council [2020] UKSC 3.

Given the centrality of policies to modern administrative decision-making, and the centrality of interpretation to modern litigation, there is a vast amount of case law concerning the interpretation of administrative policies. In an article, ‘The interpretation of policies in administrative law: the significance of audience’ (2024) 44(2) Legal Studies 295, I sought to provide a framework for how the courts should approach these cases.

One method which I suggested was unhelpful was what I called the “negative instruction”: that policies should not be interpreted as if they are statutes. The courts have referred to this idea scores of times in the cases, but it is not a technique which provides much guidance. My encouragement to the courts to reject it has been conspicuously unsuccessful, as can be seen from the Court of Appeal referring to the Policy not being a statute.

By contrast, I suggested that courts interpreting policies should determine who is the legitimate audience of a policy. Having done that, the court should ascertain who would be the “least expert reader” of the policy, and seek to interpret the policy as would that reader. In the remainder of this post, I will try to apply my own approach to the interpretation of the Secretary of State’s Policy.

The first step is to identify the audience of the Policy. This of course includes the Secretary of State as decision-maker. But would it include the members of Palestine Action, other terrorist groups, or groups suspected of terrorism? One might imagine that the members of such groups may be aware of the risk of proscription, and the Policy which may be applied when a decision on proscription was made.

However, my approach involves not so much ascertaining the audience of a policy, as its legitimate audience. In the article, I suggested that there may be elements of the audience of a policy which might not have a legitimate interest in its reasoning, giving the example of individuals considering whether they could get away with committing a criminal offence without being charged. They would not have a legitimate interest in the Crown Prosecution’s charging guidance. (There may be exceptions to this – such as a policy being required in relation to prosecution for assisted suicide by R (Purdy) v DPP [2009] UKHL 45 – but such circumstances are highly unusual.) By the same token, a group concerned in terrorism could be said not to have a legitimate interest in seeing how much they could support terrorism, without being subject to proscription; the same would apply to an individual considering joining the group. A group which is only suspected of but not actually concerned in terrorism would fall outside the scope of the policy, which applies only to how to exercise a discretion in relation to groups which are actually concerned in terrorism. It could be said that the public would be a legitimate audience for policy, such that they could hold the government to account, given that “the purpose of the Proscription Policy was to render transparent some of the non-exhaustive factors that will be considered” [83]. However, this would be true in relation to most if not all policies which would affect administrative decision-making. The public’s level of interest would also be much more attenuated than a person to be subject to the policy or with a stake in the decision to be reached. Therefore, the general public would not be part of the legitimate audience of the Secretary of State’s Policy for the purpose of determining how it should be interpreted.

On this basis, the only legitimate audience of the Policy would be the Secretary of State, who would herself be applying it. There is no question of who would be the least expert reader: the question would be how a reasonable Secretary of State would interpret it. In terms of purpose of the Policy, a Secretary of State would likely view the purpose of the Policy as to provide guidance such that they did not have to reinvent the wheel. A Secretary of State, contrary to the Divisional Court’s interpretation, would be unlikely to view the Policy as constricting their choice as to what groups could be designated. On this basis, a reasonable Secretary of State’s starting point would likely be that the wording “the Home Secretary will take into account other factors, including [the five specified]” is not restrictive.

In her post on the Divisional Court’s decision, Daniella Lock interestingly identified statements by ministers to Parliament when introducing the Terrorism Act, and argued that this shed light on the interpretation of the Policy, which had existed since being given as assurance to Parliament. This raises the question whether the Policy will necessarily have kept the exact same meaning in the quarter century since. I argued that whether a policy’s meaning might change over time would depend on the view which the least expert reader would take of it. Here, it seems likely that a Secretary of State would consider that the meaning of the Policy could adapt to the acutely fact-sensitive national security context, and would not necessarily view themselves as bound by the wider statements made at the time the Policy was first formulated.

One point which a Secretary of State, as an expert in the field would expect to take into account would be the implications of the interpretation of a particular policy. If the policy is given a narrow interpretation, a Secretary of State would be aware that this could have a negative effect in relation to their attempts to counteract terrorism.

In short, viewing the matter from the position of the least expert legitimate member of the audience of the policy – a reasonable Secretary of State – would likely lead to the same conclusion as that reached by the Court of Appeal. That said, looking at the case through the lens of the legitimate audience of the policy may serve to provide much-needed clarity and structure to questions of interpretation in this field.

Concluding Comments

The Court of Appeal did not focus on identifying the legitimate audience of the Policy, and how that audience might have interpreted it. However, it seems likely that such an approach would have supported the meaning which the Court ascribed to the Policy. This approach, I respectfully suggest, provides clarity, and help in resolving questions of interpretative technique, than trying to interpret a policy differently to legislation.  

The author is grateful to Kenny Chng, Leah Trueblood and Se-shauna Wheatle for extremely helpful comments on earlier drafts of this post; all views and errors are my own.

Alistair Mills is the Dias College Assistant Professor in Law at Magdalene College, Cambridge; an Affiliated Lecturer at the Faculty of Law, University of Cambridge; and an Associate Member of Landmark Chambers.

(Suggested citation: A. Mills, ‘The Interpretation of Policy and the Proscription of Palestine Action’, U.K. Const. L. Blog (23rd June 2026) (available at https://ukconstitutionallaw.org/))