In R v ABJ [2026] UKSC 8 a unanimous Supreme Court ruled that the offence of expressing support for a proscribed organisation, as defined in the Terrorism Act 2000, is not a disproportionate interference with the right to freedom of expression under the European Convention on Human Rights. The Court’s verdict was no surprise: the Court of Appeal had reached the same conclusion ([2024] EWCA Crim 1597) and the case sits alongside earlier appeal court rulings upholding the compatibility with Convention rights of other Terrorism Act offences relating to proscribed organisations: notably, R v Choudary [2016] EWCA Crim 61 (on inviting support for a proscribed organisation) and Pwr v DPP [2022] UKSC 2 (on carrying or displaying an article supportive of a proscribed organisation).

The offence at issue in ABJ is a relatively new one, having been added (as section 12(1A) of the Terrorism Act 2000) by the Counter-Terrorism and Border Security Act 2019. Both the legislation and the Supreme Court’s interpretation of it require careful scrutiny.

Counter-terrorism legislation in the UK has long included offences of soliciting or inviting support for a proscribed organisation: see, for example, section 2 of the Prevention of Terrorism (Temporary Provisions) Act 1989 and section 30 of the Northern Ireland (Emergency Provisions) Act 1996. When the Court of Appeal ruled in Choudary that the successor provision, section 12(1) of the Terrorism Act 2000, was not a disproportionate interference with freedom of expression, the court emphasised the narrowness of that provision (and, thus, the narrowness of the criminalisation of speech):

the section only prohibits inviting support for a proscribed organisation … It does not prohibit the expression of views or opinions, no matter how offensive, but only the knowing invitation of support from others for the proscribed organisation (para [70]).

The targeted nature of the offence was offered as a reason for the court ruling it to be compatible with freedom of speech.

In the years between Choudary being decided and the 2019 Act being enacted the UK suffered a series of deadly terrorist attacks. Jo Cox MP was murdered in 2016. Six people were killed on Westminster Bridge in March 2017. Twenty-three people were killed at an Ariana Grande concert in Manchester in May 2017. And the following month eleven people were killed at London Bridge. In addition to the fatalities nearly 200 people required hospital treatment as a result of these atrocities. A subsequent review of counter-terrorism strategy concluded that, in addressing the dangers of radicalisation, existing offences were inadequate. Hence the new section 12(1A). Relying on reports of the Independent Reviewer of Terrorism Legislation, the Supreme Court in ABJ noted that “the threat of terrorism in the United Kingdom now comes principally from persons who act alone, using bladed weapons or motor vehicles, and have been radicalised via the internet” (para [53]). Reviewing the law in 2023 the Independent Reviewer concluded that section 12(1A) should not be amended.

There were two appeals in ABJ. Their facts are some distance removed from the circumstances whereby a lone wolf is radicalised online. In the first, a speaker at a Palestine Solidarity Campaign event in Brighton said on 8 October 2023 that what had happened the previous day in Israel—when 1,195 people were massacred by Hamas—was “a victory”, was “beautiful and inspiring”, and that “we need to celebrate these acts of resistance”. In the second, a protester on 17 October 2023 held a placard outside the gates of Downing Street which read “HAMAS is the vanguard of the Resistance” and spoke through a loudhailer that: “I support the physical force resistance in Palestine … I support armed physical force …”. Both individuals were charged under section 12(1A). (Hamas’ military wing has been proscribed in the UK since 2001 and the entirety of the organisation was proscribed in 2021.)

At the time of the Supreme Court hearing neither individual had been tried. The Supreme Court was concerned with the preliminary question of whether a conviction under section 12(1A) would be compatible with the Article 10 Convention right to freedom of expression.

The focus of the Supreme Court’s judgment, which was delivered by Lord Reed, was on the detailed terms of section 12(1A)—i.e., on the ingredients of the offence. The provision reads as follows: “A person commits an offence if the person (a) expresses an opinion or belief that is supportive of a proscribed organisation, and (b) in doing so is reckless as to whether a person to whom the expression is directed will be encouraged to support a proscribed organisation”. In Choudary the Court of Appeal had been concerned to emphasise that the law plainly distinguishes between “saying that one agrees with certain views” and “supporting a proscribed organisation”. Lord Reed in ABJ insisted that this remains the position even as regards section 12(1A). He explained as follows:  

That provision [section 12(1A)] does not make it an offence to express a personal opinion or belief, or to invite someone else to share that opinion or belief. Nor does it make it an offence to express support for a proscribed organisation. Proof that a person had done so would not be sufficient to support a conviction. The short description of the offence in the indictments against the appellants is therefore liable to mislead. The offence is not committed by ‘expressing support for a proscribed organisation’. An offence is committed only if a person expresses such support and ‘in doing so is reckless as to whether a person to whom the expression is directed will be encouraged to support a proscribed organisation’ (para [38]).

Thus, expressing an opinion or belief that coincides with or is shared by a proscribed organisation is not sufficient to meet the terms of section 12 (1A). Neither will the expression of an opinion or belief supportive only of the aims of a proscribed organisation (whether such aims be a united Ireland or an independent Palestine, for example). Rather, the opinion or belief must be supportive of the organisation itself and, moreover, the prosecution will have to prove that the person charged with the offence knew that his or her expression was supportive of the proscribed organisation. Whether a statement is supportive of an organisation is a question of fact (not law) and is therefore a matter for a jury to determine. Finally, as we have seen, the offence is not committed unless the speaker was reckless as to whether someone to whom the speech was directed will be encouraged to support a proscribed organisation. The word “directed”, ruled the Supreme Court, further limits the scope of the offence. ABJ’s speech, for example, may have been “directed” to the people in the crowd who heard her in Brighton, but was not directed to the people who saw a recording of her speech after it had been posted online by the Daily Mail.

The Supreme Court ruled that, understood properly, the offence in section 12(1A) could not be condemned as being a disproportionate interference with freedom of expression. If all of the ingredients of the offence are proven, there is no room to contend that a conviction would be a disproportionate interference with the speaker’s right to free speech (paras [134]-[135]). There remains ample room in the United Kingdom to argue, for example, that Palestine should be free of Israeli oppression or that Ireland should be united without expressing support for any proscribed organisation.

Significantly, then, ABJ is not one of those rulings that closes down an ab ante challenge to the validity of legislation only to leave open the possibility that particular uses of the legislation may later be challenged as being in breach of Convention rights (cf Safe Access Zones [2022] UKSC 32, paras [12]-[18]).

Equally significantly, ABJ continues a rapidly growing line of recent appeal court authority to have found that once the ingredients of an offence are proven there can be no contention that a conviction would be a disproportionate interference with Convention rights. This line of authority is now so strong that it may be said essentially to have confined the highly controversial Ziegler case to its facts (DPP v Ziegler [2021] UKSC 23). In that case, the Supreme Court ruled that the prosecution of a protester for the offence of wilful obstruction of the highway (under the Highways Act 1980, section 137) would be lawful only if it was not a disproportionate interference with the protester’s Article 11 Convention right to freedom of peaceful assembly. The contrary approach has now been taken not only in ABJ, but also in relation to offences such as aggravated trespass, public nuisance, and interference with the use or operation of key national infrastructure (contrary to the Public Order Act 2023, section 7). Thus, if the ingredients of any of these offences are proven, it cannot be contended that a conviction would be disproportionate. (See, respectively, DPP v Cuciurean [2022] EWHC 736 (Admin), R v Brown (James Hugh) [2022] EWCA Crim 6, and R v Sarti [2025] EWCA Crim 61.)

This line of authority, along with ABJ itself, has two noteworthy constitutional consequences. The first is to shift the focus away from the various elements of the proportionality doctrine, onto forensic judicial examination of the multiple ingredients of offences. There is strikingly little in Lord Reed’s judgment in ABJ about “rational connection”, “least intrusive available means”, or “fair balance”. At no point, for example, did the Supreme Court reflect on the apparent lack of a rational connection between the purpose of the new offence (online radicalisation of lone-wolf attackers) and the facts of the two cases on appeal. This is not because the Court was unconcerned about any such disconnect: it is because the Court considers that the problem can (and should) be addressed through the ordinary rigours of a criminal trial rather than via the application of overarching principles of human rights law. Lord Reed was quite explicit about this. Given “the importance of freedom of expression, and the risk that an overly broad application of section 12(1A) might discourage legitimate public debate”, trial judges should “be robust”, he stated, in exercising their powers of direction (para [131]). Lord Reed did not shy away from commenting on how the appeals in front of him illustrated the point: could a jury be sure that the first appellant had expressed an opinion which was objectively, and which she knew to be, supportive of Hamas (an organisation she did not mention)? And, as regards the second appellant, could a jury be sure that anyone to whom the expression in that case was directed would be encouraged to support Hamas?

The second is to underscore that, in the UK’s constitutional order, even if proportionality is ultimately a question of law for the courts to rule on, it is parliamentary government rather than the appeal courts that will play the lead role in seeking to balance individual rights against the demands of the public interest. Thus, it is the constitutional responsibility of Parliament and government to ensure that the law of the United Kingdom strikes a fair balance between the right to freedom of expression and the public interest in countering terrorism (see para [106]), just as it is for Parliament and government to ensure that the law strikes a fair balance between the right to peaceful protest and the public interest in the life of the community not being unreasonably disrupted.

The appeal courts are but a backstop. When they need to, they will rule that government (or the police) have acted unlawfully, or they will declare that Parliament has legislated incompatibly with rights. But, in the ordinary course of affairs, the struggle to protect rights remains a matter of parliamentary deliberation and debate rather than one of appeal court litigation. Some will condemn that as “conservative”. Others will prefer to see it as being consistent with the UK’s long-established constitutional traditions. Perhaps these are two ways of saying the same thing.

Adam Tomkins is the John Millar Professor of Public Law at the University of Glasgow

(Suggested citation: A. Tomkins, ‘On ABJ: Proscribed Organisations, Proportionality, and Freedom of Speech’, U.K. Const. L. Blog (20th April 2026) (available at https://ukconstitutionallaw.org/))