The Grand Chamber Judgment in Hassan v UK

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The eagerly-awaited Grand Chamber judgment in the case of Hassan v UK has now been released, and its importance for anyone interested in extraterritoriality, detention and the relationship between international humanitarian law (IHL) and international human rights law (IHRL) cannot be overstated. For the first time in its history, the Court has explicitly offered its view on the interaction between IHL and IHRL and the operation of the Convention, particularly the right to liberty, in the context of an international armed conflict.

A good overview of the facts of the case and the Court’s judgment can be found here, and they will not be repeated in this post. Instead, I want to offer some initial thoughts on the Court’s reasoning with regard to Article 5 ECHR and, more specifically, its approach to treaty interpretation.

The question before the Grand Chamber was whether the internment of the applicant’s brother, which appeared to conform with the Third and Fourth Geneva Conventions, could be considered consistent with Article 5 ECHR, notwithstanding the absence of any derogation by the UK. At a very general level, the Court effectively had two options here. On the one hand, it could have followed the path it appeared to be laying in its previous case-law, particularly in Al-Skeini and Al-Jedda, and hold that, where jurisdiction exists and where no lawful derogation has been made, the State remains bound to honour its obligations under the ECHR as ordinarily interpreted. Had the Court taken this approach, the Contracting States may eventually have conceded defeat and begun derogating in extra-territorial contexts. (Incidentally, the Court continued to avoid explicitly engaging with the permissibility of extra-territorial derogations.) Instead, the Court adopted the alternative approach, interpreting the ECHR so as to leave room for the broader powers that States have under IHL. Thus, it effectively read into Article 5(1) ECHR an extra permissible ground for detention where consistent with the Third and Fourth Geneva Conventions, and it read down the requirement of habeas corpus in Article 5(4) to allow for the administrative forms of review under the Fourth Geneva Convention.

Let’s begin with a few, in my view, positive points about the Court’s approach here. First, and perhaps most importantly, the Court rejected the UK’s principal argument that IHL as the lex specialis precluded jurisdiction arising under Article 1 ECHR (para 77). To have followed this would effectively have been to displace the entire Convention where IHL applies. Instead, the Court adopted a more nuanced, case-by-case approach which looks at the specific right at issue. This enables the Court to retain its oversight function by assessing the legality of the actions of Contracting Parties through the prism of IHL.

Second, in its assessment of the merits, and contrary to the approach advocated by the UK government, the Grand Chamber does not rely on the notion of lex specialis. Instead, its reasoning rests on two tools of treaty interpretation under Article 31(3) of the Vienna Convention on the Law of Treaties (VCLT), namely subsequent practice (Article 31(3)(b)) and other relevant rules of international law applicable in the relations between the parties (Article 31(3)(c)) (paras 100-102). The notion of lex specialis has in many ways confused the whole debate on IHL and IHRL, with many seeing it as something approaching a standalone principle with normative content that is capable of indicating which norm is special and which general. In reality, the notion of lex specialis is just a useful shorthand for one particular factor (among many) that we may take into account when interpreting a treaty; it most certainly does not answer the question on its own of which rule governs. The Court’s reliance on subsequent practice and Article 31(3)(c) helps to move beyond the often obfuscatory invocation of lex specialis.

Third, and related to the previous point, the Court does not simply submit Article 5 ECHR to the more permissive treaty standards in the Third and Fourth Geneva Conventions. Rather, its approach to this relationship is more symbiotic. This is seen in its interpretation of the requirement of a ‘court’ in Article 5(4), where it states that, whilst this could be read as permitting use of a ‘competent body’ as provided for under Articles 43 and 78 of the Fourth Geneva Convention, that body ‘should provide sufficient guarantees of impartiality and fair procedure to protect against arbitrariness’ (para 106). By virtue of the continued operation of Article 5(4) in the background, the Court required of the ‘competent body’ more than the text of Article 43 of the Fourth Geneva Convention itself does.

Finally, the Court makes clear that its reasoning is limited to international armed conflicts, where IHL treaty law is relatively detailed; the pure human rights approach taken in Al-Jedda is thus preserved, and the judgment similarly seems compatible with the recent UK High Court case of Serdar Mohammed v Ministry of Defence, both of which concerned non-international armed conflicts.

Let us now turn to some of the deficiencies in the Court’s reasoning. In particular, whilst its reliance on Articles 31(3)(b) and (c) VCLT over the lex specialis maxim did, as noted, encourage greater clarity, it is not clear that either subsequent practice or Article 31(3)(c) quite so readily points to the conclusion at which the Court arrived. Regarding subsequent practice, the Court took the view that the absence of derogations from Article 5 ECHR by States when detaining in the context of international armed conflicts indicates that that provision is not considered to exclude detentions pursuant to the Third and Fourth Geneva Conventions. However, such practice does not necessarily support the view that Article 5 ECHR must yield to IHL. Derogations may not be taken for any number of reasons. In their partly dissenting opinion, Judges Spano, Nicolaou, Bianku and Kalaydjieva note that the absence of derogations in such situations is underpinned more by States’ continued attempts to avoid conceding the extraterritoriality of the Convention than any view as to the relationship between IHL and IHRL (para 12). Indeed, if the Court draws such a clear conclusion from this subsequent practice, why should we not similarly draw the conclusion that the absence of derogations in the extra-territorial context confirms the non-applicability of the ECHR in all such situations? The Court has clearly rejected this view, and it is not clear why it places so much emphasis on this practice here.

There is also a more general question about the propriety of using subsequent practice in a manner that effectively modifies treaty obligations. The Court refers to its previous case-law where it has accepted that the Convention can be modified by ‘a consistent practice on the part of the High Contracting Parties’ (para 101). I am of the view that subsequent practice can, in certain circumstances,have such an effect, where that practice clearly indicates a common intention on the part of the States parties. However, there is much debate on this issue, and one might have expected the Court to consider some contrary views (see the discussion in the Second Report of Special Rapporteur Georg Nolte, 65th Sess, ILC 2014, paras 117-142). Indeed, José Alvarez notes that, ‘where a treaty creates a third party beneficiary … as in the case of human rights treaties … the capacity for the states parties to modify their treaty through practice faces additional constraints’ (G Nolte (ed), Treaties and Subsequent Practice (OUP 2013), p 126). The Court’s failure properly to engage with this important point of general international law risks undermining its reliance on subsequent practice in this manner.

Regarding the Court’s use of Article 31(3)(c), it might similarly be argued that one should not be too quick to assume that this provision provides all the answers. Indeed, it is not uncommon for States to have adopted inconsistent obligations under different treaties. In such instances, it will often be a political question as to which obligation will be followed and which breached. The law of State responsibility then indicates what consequences flow from the breach. It is not immediately clear why, in the case of IHL and IHRL, it should be different. Operational practicalities certainly suggest the need for reconciliation, but at what point do we decide that reconciliation is not possible, thereby requiring derogation? Just as reliance on the lex specialis maxim cannot determine finally which rule prevails, so pointing to Article 31(3)(c) is not the end of the matter. One must then consider which rules are ‘relevant’, what weight such rules should have in interpreting the particular treaty provision and why (see, e.g., Paparinskis). Indeed, the limits of Article 31(3)(c) have been emphasised with regard to other areas of international law. In her separate opinion in Oil Platforms, Judge Higgins criticised the majority on the basis that, rather than interpreting the relevant treaty provision, they had displaced the applicable law by relying on Article 31(3)(c) (paras 45–9). The symbiotic approach taken by the Court in Hassan goes some way to pre-empting this line of critique, yet it remains unclear why the Court chose the particular approach it did. Indeed, international criminal law has elaborated the requirements in Articles 42 and 43 of the Fourth Geneva Convention. Why did the Court not similarly incorporate these?

Finally, a number of questions are left open by the Court’s judgment. For example, whilst the Court considers that Article 5(4) might be read down so as to allow for a ‘competent body’ under Article 43 of the Fourth Geneva Convention to review internment, it is unclear whether it would take the same approach to the Third Geneva Convention, which provides no review of the legality or necessity of combatant internment. Given the weight the Court seems to place on the existence of review procedures for civilian internees under the Fourth Geneva Convention (para 106), it seems far less likely that it would allow a State to rely on the Third Geneva Convention to justify the absence of any form of review of combatant internment outside the context of derogation. (The different approach under the Third Geneva Convention was recognised, with concern, in the partly dissenting opinion (para 5)). The Court might have gone some way to addressing such unanswered questions if its reasoning, particularly with regard to its invocation of Article 31(3)(c), had been more detailed.


Hassan reflects an extremely important decision in the ECtHR’s history. Whilst rejecting the UK’s principal argument that IHL excluded jurisdiction arising under Article 1 ECHR, it interpreted the requirements of Article 5 so as to make room for the more permissive regimes under that body of law. The Court is right to interpret Convention rights in a contextual manner. However, its reasoning, although an improvement on abstract statements of lex specialis, leaves a number of questions unanswered. One is also left with the question of whether the alternative approach, of demanding the Contracting Parties to derogate in order to access rights under IHL that the text of the Convention does not appear to permit, might eventually have been accepted by States and created a more robust mechanism for protecting rights.

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Simon Rau says

September 17, 2014

Dear Lawrence Hill-Cawthorne,
thank you for your insightful post.
In Hassan, the ECtHR sticks to its tendency to come up with creative solutions in cases posing an impossible dilemma. To be honest: Could one have expected the court to declare that all internment in the IAC in Iraq violated Art 5 ECHR thus opening the floodgates to potentially thousands of complaints? This would probably also have been a significant contribution to alienating the UK further from the convention system. The recurrence to subsequent practice can certainly be criticized as the dissenters do, but it is a legally plausible way out of a tricky situation. Is it less "obfuscatory" than a resort to lex specialis would have been? I am not sure. It definitely has the advantage of allowing the court to engage in a case by case analysis as you point out. This case by case approach, dressed in the language of subsequent practice, could however also be seen as a possibility for the court to pick the most opportunistic solution whenever the ECHR and IHL conflict. After all, I think that a recourse to lex specialis could have yielded the same result as this smart, but not entirely convincing turn to subsequent practice.


Manuel says

September 17, 2014

Dear Lawrence, thank you for your excellent analysis of the Court's judgment. I would like to post two questions regarding your conclusions.
Your article ends with question whether the alternative approach (derogation) would have created a more robust mechanism of creating rights. I'm not quite sure why the alternative option would be considered to be more robust.If the UK had derogated from Article 5, then the court couldn't have adopted the symbiotic approach of combining IHL and ECHR rules, since there simply wouldn't have been any human rights obligation to comply with in the first place. Only IHL would have been relevant to the Court. Wouldn't the derogation approach therefore be less protective than the approach taken by the Court? Or would the wording of Art 15 "to the extent strictly required" enable the Court to add human rights evaluations?

The second question resolves around the distinction between IACs and NIACs in the Court's Judgment. In § 104 the Court stresses that its symbiotic approach is only applicable in IACs, since "the taking of prisoners of war and the detention of civilians who pose a threat to security are accepted features of IHL". But why should it from the Court's point of view, i.e. a human rights point of view, matter whether the detention took place in an IAC or NIAC? Why should the interpretation of Article 5 ECHR be dependent on whether the armed conflict is international or internal?
Thank you

Lawrence Hill-Cawthorne says

September 18, 2014

Dear Simon,

Thanks very much for your comment. I fully agree with you that there are any number of complicated, extra-legal considerations that always lurk in the background in such cases. In this post, I am merely focussing on the specific legal tools to which the Court resorted in its reasoning.

I do think that its reliance on Articles 31(3)(b) and (c) offers the potential for greater clarity in the reasoning in these cases, than a blanket reliance on the lex specialis maxim might. This is because of the way in which the maxim has been invoked since the ICJ offered it as a potential tool in the Nuclear Weapons case. The ICJ’s use of it in that case was perfectly reasonable – the notion of ‘arbitrary’ deprivation of life is context-specific, and in the context of an armed conflict, we might look to the rules States have developed for such situations. If to do so helps us to develop a common, objective intention of the States parties, then it can facilitate the treaty interpretation process. Unfortunately, subsequent to this, the notion of lex specialis has been invoked in far less nuanced ways, with suggestions that simply identifying a particular norm as self-evidently ‘special’ is the end of the matter. Looking to Articles 31(3)(b) and (c) helps to protect against the ECtHR’s judgment here being used in the same way (although by no means does it ensure this won’t happen). The ECtHR might well have reached the same conclusion through invoking lex specialis, but others may have read it in a far more broad-brush manner. This all relates to the use of lex specialis at the merits stage. Of course, had it accepted the UK’s lex specialis point in relation to the latter’s jurisdictional objections, it would have been very different – the Convention would not apply, and the Court’s supervisory role would be precluded.

Best wishes,

Lawrence Hill-Cawthorne says

September 18, 2014

Dear Manuel,

Thanks very much for your comments and questions. Regarding your first point, on whether derogation would be more protective, I think this is a very important point. I do think it could be more protective than the approach taken by the Court in Hassan. Most importantly, derogation does not grant a State complete freedom in what it may do. Rather, it enables States to adjust their obligations according to the specific circumstances. Under the key human rights treaties, derogation is subject to demonstrating necessity and proportionality – importantly, these must be shown both with regard to the general derogation in the particular situation and with regard to each measure adopted pursuant to the derogation. Whereas the Court in Hassan appears to read down the Convention to leave room for the IHL rules on internment (at least those in the Fourth Geneva Convention) whenever the latter apply, relying on derogation would enable a State to rely on those IHL rules only when one could say that it was actually necessary and proportionate in the prevailing circumstances to do so (the existence of an international armed conflict in itself may not be sufficient here – consider, for example, domestic internment of so-called ‘enemy aliens’). In addition, derogation from Articles 5(1) and (4) would not necessarily extinguish those provisions in full; rather, derogation therefrom would be permissible only to the extent that is necessary and proportionate (hence, it need not exclude the symbiotic approach taken by the Court in Hassan).

Your second question, on why the Court’s approach should be limited to international armed conflicts, is also very interesting. Had the Court taken the alternative, what might be termed ‘pure’ ECHR approach (that is, looking to the ECHR and the Court’s case law only, without introducing external norms from IHL), conflict characterisation would likely be irrelevant – the Convention applies generally, in peacetime, internal tensions, non-international armed conflicts and international armed conflicts, and a State party would be bound by the Convention in all of these situations unless it has derogated lawfully (this, of course, does not preclude contextual interpretation). However, because the ECtHR took the alternative path of looking outside the Convention to rules of IHL, the question of conflict characterisation becomes relevant to the question of whether a State violates the ECHR, and in particular Article 5. This is because, whereas the treaty law of international armed conflict contains rules on when belligerents can intern, inter alia, combatants and civilians, neither conventional nor customary international law applicable in non-international armed conflicts does. Hence, the Court cannot look to IHL where a State interns in a NIAC (for there are no such rules) and nor does subsequent practice suggest the non-applicability of Article 5 ECHR in such situations; the Court must, therefore, rely on the ordinary framework in the Convention to judge the legality of internment in such situations (absent derogation, internment would then be unlawful).

Best wishes,

Simon Rau says

September 18, 2014

Dear Lawrence,
thank you for your response.

I find it interesting how the court rushes in a single paragraph to the conclusion that there is indeed subsequent practice which qualifies Art 5(1) with regard to the permissible grounds of detention to allow for internment in IAC. In fact, it only states that it is state practice not to derogate, but it does not examine if this practice really established an agreement as to the ECHR's interpretation. This is then backed up with extreme harmonious interpretation under Art 31(3)(c) VCLT against the strict wording of Art 5(1) ECHR.
With regard to Art 5(4) the court does not even bother to look at the VCLT, but starts its argument with the observation that "[...] it might not be practicable [!!!], in the course of an international armed conflict, for the legality of detention to be determined by an independent “court” in the sense generally required by Article 5 § 4[...]", while requiring, as you pointed out, procedural guarantees that are stronger than those under GC IV.

Why? I think the key to understanding this judgment really is that in the light of practical and especially political considerations this is how the court considered that the balance between a peacetime ECHR and an IHL framework could adequately be struck – this allows for internment and tilts the balance slightly towards human rights with regard to review. I am not saying that this is a bad decision. Rather, it seems to be rather reasonable given the circumstances of the case.

At the same time the court would obviously not yield to the UK's argument that IHL excluded its jurisdiction, as this would have undermined its clout. After all, most international courts seem rather keen on increasing there influence – Koskenniemi speaks of a "struggle for jurisdiction" in this regard.

Best, Simon

Jordan says

September 21, 2014

Perhaps in the future attention to other relevant international law will include U.N. 55(c), 56, and 103 (incorporating customary human rights and providing a primacy) as well as human rights jus cogens (e.g., the list in the HR Comm. Gen. Comm. No. 24).

Martin Scheinin says

October 23, 2014

Hassan clearly is an important case, and the excellent blog posts by Lawrence Hill-Cawthorne and Marko Milanovic provide great analysis. Where I propose a more cautious approach in reading the judgment is the issue whether the ECtHR approved administrative review as sufficient during IAC for compliance with ECHR Art 5 (4). Lawrence Hill-Cawthorne reported the Court to have "read down the requirement of habeas corpus in Article 5(4) to allow for the administrative forms of review under the Fourth Geneva Convention". This comes with his proposed qualification, though: "By virtue of the continued operation of Article 5(4) in the background, the Court required of the ‘competent body’ more than the text of Article 43 of the Fourth Geneva Convention itself does." So, we would get a simultaneous reciprocal lex specials effect between IHL and IHLR, if you so wish.

I propose to assume less of "reading down" into para. 106 of Hassan. In that para. the ECtHR is saying that even if it might not be practicable to secure court review of detention during war, states nevertheless must comply with Art. 5 (4), even if coupled with a flexible understanding of what is a "court". The key sentence comes in para. 110: "Moreover, in the light of his clearance for release and physical release within a few days of being brought to the Camp, it is unnecessary for the Court to examine whether the screening process constituted an adequate safeguard to protect against arbitrary detention." Hence, the duration of time spent in detention may be a crucial factor in assessing compliance with Art. 5 (4) during IAC, including as to when exactly access to court will in practice materialise. It must exist in principle, and it must kick in at some point. Let's not forget Boumediene v. Bush.

True, the ECtHR was far from being clear on this point. But my suggested reading would be in line with General Comment No. 29 by the Human Rights Committee (true, I was involved) and the position that ICCPR Art. 9 (1) - prohibition against arbitrary detention - and Art. 9 (4) - requirement of court review of any form of detention - are both non-derogable elements of the right to liberty of the person. That would have to be the human-rights-compatible way of applying IHL in the 21st century.