Terrorism and free speech: the criminal law and the Convention
17 March 2026
By Samuel Talalay
Introduction
Article 10 of the European Convention on Human Rights (“ECHR” or “the Convention”) provides qualified protection for speech. Section 12(1A) of the Terrorism Act 2000 (“the 2000 Act”) criminalises certain speech acts relating to proscribed organisations. In the case of R v ABJ; R v BDN [2026] UKSC 8the Supreme Court was asked to decide whether these two things could be reconciled: is s 12(1A) of the 2000 Act compatible with the Convention?
In its judgment, given on 26 February 2026, the Court answered this question with an unequivocal ‘yes’. The offence introduced by s 12(1A) was prescribed by law and necessary in a democratic society. Crucially, conviction would always represent a proportionate interference with the defendant’s Article 10 right to free speech where the elements of the offence, properly understood, were made out.
In providing such a resounding answer, however, the Court risks setting the bar too high for legislative provisions to be compatible with the Convention.
The criminal legislation
The Terrorism Act 2000 created a range of measures to combat both domestic and international terrorism. It is divided into eight parts, the second of which concerns proscribed organisations. Sections 11 to 13 of the Act provide for offences relating to such organisations.
The 2000 Act was amended by the Counter-Terrorism and Border Security Act 2019 (“the 2019 Act”) to include a new s 12(1A) which, loosely speaking, made it an offence for someone to express support for a proscribed organisation while knowing the risk that this support might encourage someone else to support the organisation.
More precisely, a person commits the offence, contrary to s 12(1A), just when that 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.
Case overview
The two Appellants, ABJ and BDN, were charged with offences under s 12(1A) of the Terrorism Act 2000 for their conduct on 8 and 17 October 2023, respectively. They were anonymised pending their Crown Court jury trials.
The first Appellant (“A1”) gave a four-minute speech in Brighton on the day after the October 7 attacks in Israel at an event for the Palestine Solidarity Campaign, the contents of which are reproduced in the judgment at [6]. The case against her was that she expressed an opinion or belief that was supportive of Hamas, a proscribed organisation, contrary to s 12(A) of the 2000 Act (i.e. with the appropriate recklessness).
The second Appellant (“A2”) stood outside Downing Street holding a placard and a megaphone. The two sides of the placard read “HAMAS is the vanguard of the Resistance – Avi Shlaim” and “You won’t destroy HAMAS – Tony Blair”. He asked a passerby to record a video on his (A2’s) phone, before making short remarks about events in Israel-Palestine (reproduced at [12]).
In preparatory hearings, rulings were made against both Appellants on questions related to the compatibility of the statutory provision under which they were charged with their Article 10 Convention right to free speech. On appeal, the Court of Appeal heard their cases together: ABJ v R [2024] EWCA Crim 1597. It dismissed both appeals but certified two points of law of general public importance. The Supreme Court granted permission on the first point ([1]):
Do the terms of section 12(1A) Terrorism Act 2000 represent a disproportionate interference with the appellant’s rights under article 10 of the European Convention on Human Rights? In the event that they do, is it possible to read down the terms of the offence to render them compatible?
The decision of the Supreme Court
In determining the compatibility of s 12(1A) and Article 10 ECHR, the task of the Court ([2]) was to establish the elements of the statutory offence and determine their compatibility with Article 10 ECHR.
The Court considered the ingredients of the offence at [57] to [81], summarising the seven elements of the offence at [82].
The second task, summarised at [88] to [89], comprised several related but distinct questions arising from the Appellants’ divergent cases. A2’s challenge to s 12(1A) was broad, and gave rise to the following two questions:
- Is the offence too vague to be “prescribed by law” (a condition that any interference with a qualified Convention right must meet to avoid being a violation of that right)?
- Does the offence fail to balance appropriately the legitimate interests pursued by combating terrorism with the right to free speech, such that the provision does not meet the requirement of being “necessary in a democratic society” and is therefore necessarily incompatible with Article 10?
The first Appellant raised a narrower issue for the Court to grapple with:
- Is the risk that a given conviction under s 12(1A) constitutes a violation of that individual defendant’s Article 10 rights such that a separate proportionality exercise is required as part of each trial?
Question 1: Prescribed by law
The Court rehearsed the familiar points from [26] of Huvig v France (1990) 12 EHRR 52 and [27] of Kruslin v France (1990) 12 EHRR 547: a measure will be prescribed by law only if it has a basis in domestic law and the “quality of the law in question” ([91]) meets the requisite standards of accessibility and foreseeability.
Given that the impugned measure was itself a provision of domestic law, the question for the Court was whether the conditions of accessibility and foreseeability were met. The Court had no trouble concluding, at [96], that they were. Section 12(1A) certainly did “not present greater difficulties of definition” than an array of international legal comparator provisions considered at [97], all of which the European Court of Human Rights (“ECtHR”) had found to meet the relevant test.
Question 2: Necessary in a democratic society
An interference with an individual’s right to free speech is necessary in a democratic society if, and only if, it is a proportionate means of achieving one of the legitimate aims listed in Article 10(2) of the Convention.
Section 12(1A), which was “intended to address the danger of radicalisation” ([98]), pursued a number of legitimate aims included in that provision, notably: “the protection of national security and public safety, the prevention of disorder or crime, and the protection of the rights of others” ([99]).
Considering the proportionality of the means of achieving those aims, the Court noted that the provision required “a compelling justification” in light of its being “a content-based restriction on freedom of expression” ([103]).
Set against this, at [104], was the “pressing social need” to combat “the highly dangerous consequences” associated with “the expression of opinions or beliefs which are supportive of proscribed organisations”. The Court also reminded itself, at [106], of the need to “respect the institutional expertise and constitutional legitimacy underlying the judgment” of the government and Parliament, whose careful consideration of the proportionality of the legislative interference with free speech, both during and after the passage of (what became) the 2019 Act, was considered in some detail at [42] to [55].
The Court summarised, at [125], five factors that the ECtHR – whose caselaw on this subject was explored at [110] to [123] – had generally “treated as important”: the context of the words spoken; whether the words encourage violence; the size of any audience to the speech; whether the words amount to an apology for terrorism; and the severity of any penalties imposed.
In light of all these considerations, the Court concluded, at [134], that the provision was necessary in a democratic society.
Question 3: Proportionality exercise in individual cases
By its answer to A2’s principled challenge to s 12(1A), the Court necessarily rejected A1’s more modest contention that convictions under that provision might sometimes represent a disproportionate interference with a defendant’s Article 10 right to free speech, thereby requiring a separate proportionality exercise in individual cases.
The Court averred, at [135], that the proportionality of the provision had been established by the government (not least by its statement of compatibility under s 19 of the Human Rights Act 1998 when it introduced the Counter-Terrorism and Border Security Bill to Parliament) and again by Parliament (in the course of the Bill’s passage).
Interestingly, the Court alluded to its own “further assessment of the proportionality of convictions under section 12(1A) […] in the present judgment” alongside the efforts of the other branches of the state. This suggests that assessments by government and Parliament do not guarantee proportionality as a matter of constitutional logic. Rather, that conclusion was warranted by the specific assessments carried out and supplemented by the Court’s own detailed consideration of the relevant issues.
Setting the bar too high for a statute to be compatible with a Convention right?
As the Court noted at [84], the question before it was not “whether, on the facts of their respective cases, the conviction of the appellants would violate their Convention rights.” This sort of question – where the Court is tasked with assessing the permissibility of a concrete interference with an individual’s Convention rights in a particular case – is, conceptually speaking, quite straightforward. Here, the question – whether the statutory provision itself was compatible with Article 10 – was “of a more abstract and general character.”
At no point did the Court address explicitly the question of what it is for a legislative provision to be compatible with a qualified Convention right. It seemed however, at [89], to suggest that the bar is high (emphasis added):
The critical question is that identified in Safe Access Zones at para 55, namely whether the ingredients of the offence themselves strike a fair balance between the Convention rights of the defendant and the public interest in the achievement of the legitimate aim pursued, so that, if all the elements of the offence are proved, the conviction of the defendant will not result in a disproportionate interference with those rights.
The highlighted passage suggests that the provision would be incompatible if the offence could ever be made out while also constituting a disproportionate interference with Article 10 rights.
This is at odds with the answer given to the same question by Lady Hale, at [2] of her judgment in the case of R (on the application of Bibi) v SSHD [2015] UKSC 68:
It may well be possible to show that the application of the Rule in an individual case is incompatible with the Convention rights of a British partner […] It is much harder to show that the Rule itself is inevitably unlawful […] under the Human Rights Act 1998 […] the fact that it might be possible to argue that the operation of the Rule was a disproportionate infringement of an individual’s article 8 rights did not render the Rule itself disproportionate.
Arguably, the Court in the present case misunderstood the position, set out in Reference by the Attorney General for Northern Ireland – Abortion Services (Safe Access Zones) (Northern Ireland) Bill [2022] UKSC 32, which it professed to follow. In that case the Court observed, at [55], that for some criminal legislative provisions, “the offence is so defined as to ensure that any conviction will meet the requirements of proportionality”, in which case “the court does not have to go through the process of verifying that a conviction would be proportionate on the facts of every individual case.”
In the very next paragraph, at [56], the Court described an alternative scenario in which some convictions could be non-compliant – in which case legislative compliance with the Convention would require that a trial judge “construe the relevant provision in a way which renders it compatible with the Convention rights, either by interpreting it in such a way that a conviction will always meet the requirements of proportionality, or by interpreting it so as to allow for an assessment of the proportionality of a conviction in the circumstances of individual cases.”
Clearly, where it is the case that all convictions under a statutory offence are necessarily proportionate, then the provision itself will be proportionate. But that is the gold standard. The authorities are clear that that is not what it means for a legislative provision to be compatible with the ECHR – even if this judgment has unhelpfully muddied the waters.
Samuel Talalay is a pupil barrister at 1 Crown Office Row.
