Case law Developments in PIL

Which Law Governs UK’s Participation in the “War on Terror”?

This post was written by Ugljesa Grusic, Associate Professor at University College London. It offers a preview of the upcoming developments relating to Zubaydah v Foreign and Commonwealth Office, a case pending before the UK Supreme Court.

While private international law is no longer regarded as an apolitical field, it is rare for it to become directly entangled in clandestine intelligence operations, secret state deals, and egregious human rights violations. However, the UK Supreme Court is set to hear precisely such a case on 14 and 15 June 2023 in Zubaydah v Foreign and Commonwealth Office. This case is important not only because of its context, but also because it raises a crucial question of private international law. Can reasonable/legitimate expectations, justice, convenience, fairness, and appropriateness, as fundamental principles underlying the application of foreign law, be of practical relevance for determining the applicable law in difficult cases?


Abu Zubaydah, the first detainee in a CIA black site and the first subject of what the CIA euphemistically refers to as ‘enhanced interrogation techniques’, but what should rightfully be recognised as torture and cruel, inhuman or degrading treatment, is currently a ‘forever prisoner’ in Guantánamo. He is suing the UK government for its alleged complicity in the CIA’s wrongful conduct, which itself was part of the US ‘war on terror’.


Zubaydah is suing the UK government for misfeasance in public office, conspiracy, trespass to the person, false imprisonment, and negligence. The crux of the claims is that the Security Service and the Secret Intelligence Service (better known as, respectively, the MI5 and the MI6) were aware that Zubaydah was being arbitrarily detained at CIA black sites, where he was being subjected to torture and maltreatment during interrogations conducted by the CIA, but nevertheless sent questions with a view to the CIA eliciting information from him, expecting and/or intending (or at the very least not caring) that he would be subjected to such torture and maltreatment. The defendants are neither confirming nor denying these allegations.

Central Issue

The claim is brought in tort. The Rome II Regulation does not apply due to the acta iure imperii exception. Section 15(1) of the Private International Law (Miscellaneous Provisions) Act 1995 states that the choice-of-law rules for torts in the Act apply ‘in relation to claims by or against the Crown as [they apply] in relation to claims to which the Crown is not a party’. The lex loci delicti applies pursuant to section 11 of the 1995 Act. However, section 12 provides an escape clause.

In this case, the claimant (respondent in the appeal) aims to plead and establish his claim by reference to English law. On the other hand, the defendants (appellants in the appeal) argue that the laws of Thailand, Poland, Cuba (Guantánamo Bay), Morocco, Lithuania, and Afghanistan (the ‘Six Countries’, where he was allegedly detained, tortured, and mistreated) should govern.

Private international law thus becomes the focal point of the power dynamics at play in this case. Of course, the defendants are not asserting that the MI5 and MI6 officers who sent questions to their CIA counterparts had the specific laws of the Six Countries in mind as governing their actions. Rather, they are arguing that the laws of the Six Countries apply because this would make the claimant’s claim more uncertain and resource intensive and, consequently, more challenging to establish. Lane J accepted the defendants’ argument, but Dame Sharp P, Thirlwall and Males LJJ unanimously allowed the appeal.

Importance of the Case

This case holds importance for private international law for two reasons. Firstly, it highlights the role of private international law in holding the executive accountable and vindicating fundamental rights, particularly in cases involving alleged wrongs arising out of the external exercise of British executive authority. I will not discuss this aspect of the case here, except to say that I have written a whole book on the topic, Torts in UK Foreign Relations, which will be published by Oxford University Press in their Private International Law series on 13 June 2023.

The focus here is on the second important aspect of the case, which involves the reliance by the parties and the courts on reasonable/legitimate expectations, justice, convenience, fairness, and appropriateness, as fundamental principles underlying the application of foreign law, as important factors in the choice-of-law process.

As elucidated by the editors of Dicey, Morris and Collins in paragraph 1-006, ‘The main justification for the conflict of laws is that it implements the reasonable and legitimate expectations of the parties to a transaction or an occurrence.’ In the following paragraphs, the editors further assert that failing to apply foreign law in ‘appropriate cases’ would lead to ‘grave injustice and inconvenience’. As private international lawyers, we recognise these and similar principles as the truths of our field. However, courts rarely delve into the reasons for applying foreign law and the practical relevance of these fundamental principles. It is in the most difficult cases, such as Zubaydah, that courts may have to go back to the drawing board.

Consider a scenario where a person negligently injures a Ruritanian victim while driving in Ruritania. It is well-established that Ruritanian law would govern the tort in such a case. The application of Ruritanian law can be justified based on the reasonable/legitimate expectations of the parties involved. By driving to Ruritania, the tortfeasor submits to Ruritanian law, and the Ruritanian victim naturally expects the application of its own country’s law. Additionally, the application of foreign law can be explained by notions of justice, either as the attainment of individual private justice or the systemic justice derived from the appropriate allocation of regulatory authority among states.

However, do these ideas still hold weight where the victim was forcibly and unlawfully ‘extraordinarily rendered’ from one country to another, where their senses of sight and hearing were deprived during transportation using goggles and earmuffs, and where they were kept unaware of their location by their captors and torturers? What if the defendant accomplice was oblivious and indifferent to the victim’s whereabouts? And what if the objective of the claims is to hold a government accountable and vindicate fundamental rights that are part of the forum state’s bill of rights?

Parties’ Arguments

These are big questions, and I address them all in my new book. Here, I want to limit myself to summarising the parties’ arguments, based on the arguments advanced in the High Court and the Court of Appeal.

The claimant is relying on three arguments. First, the focus should be on the defendants’ alleged tortious conduct of sending questions to the CIA, rather than the conduct of the CIA. Second, the factors connecting the tort to the Six Countries are weak because the claimant had no control or knowledge of his location, the defendants were unaware or indifferent to the claimant’s whereabouts, and the claimant was effectively held in ‘legal black holes’ in the Six Countries, outside any legal system. Third, the factors connecting the tort to England are strong because the relevant conduct occurred in England, it was undertaken for the perceived benefit of the UK, the defendants acted in their official capacity under UK law, and they were subjected to UK criminal and public law.

The defendants are relying on four arguments. The first and second arguments (the relevant conduct; the strength of the relevant factors) present a mirror-image of the claimant’s first two arguments. Third, the escape clause in section 12 of the 1995 Act should be strictly interpreted. Fourth, tortious claims arising out of the external exercise of British executive authority do not require the disapplication of the lex loci delicti and the application of the escape clause, as shown by a string of cases involving the wars in Afghanistan (Mohammed v MoD) and Iraq (R (Al-Jedda) v SoS for Defence; Rahmatullah v MoD), as well as the UK’s participation in the extraordinary rendition, arbitrary arrest, torture, and maltreatment by foreign states (Belhaj v Straw), where English courts refused to apply English law.

While the High Court aligned with the defendants’ arguments, adopting a broad view of the relevant conduct and a narrow interpretation of the escape clause, the Court of Appeal was sympathetic to the claimant’s arguments. The Court of Appeal relied in its decision on reasonable/legitimate expectations, justice, convenience, fairness, and appropriateness, as is clear from these paragraphs:

41. These are strong connections connecting the tortious conduct with England and Wales. They reflect also the parties’ reasonable expectations. While it is true that the claimant himself had no connection with this country, he could reasonably have expected, if he had thought about it during the 20 years in which he has been detained, that the conduct of any country’s security services having to do with him would be governed by the law of the country concerned. As for the Services, they would reasonably have expected that their conduct here would be subject to English law …

42. … This conclusion gives effect to the principles on which the 1995 Act is founded, including the reasonable expectations of the parties, and to the general principle of private international law identified by the Law Commission “that justice is done to a person if his own law is applied”… the Services can hardly say that it would be unfair (or to use the statutory term, inappropriate) for their conduct to be judged by the standards of English law, as distinct from (for example) Lithuanian or Moroccan law.


Zubaydah is now awaiting a decision from the UK Supreme Court, which will determine whether or not English applies. Regardless of the outcome, this case is likely to become a prominent authority on the reasons for applying foreign law and the practical relevance of fundamental principles underlying the application of foreign law.

The hearing at the UK Supreme Court will be streamed live for those interested, scheduled for Wednesday and Thursday, 14 and 15 June 2023. The live stream can be accessed by following the link ‘watch live court sittings’ on the court’s home page.

4 comments on “Which Law Governs UK’s Participation in the “War on Terror”?

  1. Many thanks for this very interesting post. I must say that I have a hard time accepting that the action of a State, in particular in a core regalian function, could be governed by any other law than the law of the relevant State.

    I wonder whether the fundamental difference between English and French law has an impact on PIL. Under English law, public authorities are subject to the same torts as private individuals. In contrast, French administrative courts have developed a specific body of (administrative) law to assess the conduct of public authorities, including specific tort rules. Is it possible that English courts are more opened to the idea of applying foreign law to assess the acts of MI5 or 6 because they apply the same rules to assess the actions of private individuals and public authorities?

    In any case, your book looks very promising !

  2. Dear Gilles,

    Thank you for your message and the insightful points you raise.

    I completely agree with you. I also find it counterintuitive that the tortious liability of the UK government is subjected to foreign law if the claim concerns the exercise of the foreign relations and war powers. That was indeed the main reason why this topic has captured my interest.

    Allow me to explain the core principles of the English approach. Firstly, the King can do no wrong at common law. Secondly, individual Crown officers and servants (yes – “Crown” and “servants” is the terminology that English law still uses in this field) can be personally liable for any torts they commit in the purported exercise of executive power. This principle, often referred to as Dicey’s equality principle, as you described, differs fundamentally from the French approach. However, since the UK government can act only through the agency of its officials, whom the UK government can authorise to exercise public powers, these two ideas can be seen as somewhat contradictory. That is where the third idea comes into play.

    The third idea is based on the Crown act of state doctrine. Acts done by public officials that are authorized by the UK government lawfully exercising its foreign relations powers are regarded as acts of state and, therefore, cannot be tortious. The Crown act of state doctrine prevents the application of tort law to such acts. However, unlawful acts (ie acts that have not been lawfully authorised by the UK goverment) done in purported exercise of the foreign relations powers are not acts of state. Such acts, if contrary to tort law, are regarded as private acts for which individual public officials can be personally liable.

    The Crown act of state doctrine does not apply to extraordinary renditions and torture because the UK government cannot lawfully authorise such acts. Consequently, any liability of a UK government official or servant arising from alleged extraordinary renditions and torture can only be a personal liability for that official’s or servant’s private acts. The law treats such acts essentially as any other tortious conduct. That is why in cases that involved tortious claims arising out of the exercise of British executive authority prior to Zubaydah, the courts simply relied on the high hurdle to apply the escape clause that was established in cases of plain vanilla traffic accidents, industrial accidents, and economic torts.

    Of course, this approach doesn’t make sense in the context of cases like Zubaydah. It’s an absurd notion to suggest that MI5 or MI6 officers act in a private capacity when they share information with their CIA counterparts. If an MI5 or MI6 officer were to share classified intelligence with a foreign power in their private capacity, even if that foreign power is the US, they would be committing several criminal offences.

    That is essentially why I argue in my book that claims against the UK government concerning its external exercise of sovereign authority should be treated differently. By emphasising the public law function of such claims (holding the executive accountable and vindicating fundamental rights), it is not a huge leap to suggest that these tortious claims should be treated as public law claims (eg habeas corpus, judicial review and Human Rights Act 1998 claims) for choice of law purposes. Pure public law claims are never subjected to foreign laws, even when the challenged conduct occurs abroad.


  3. Adrian Briggs

    I am rather close to the outer edge of my comfort zone here, but it seems to me that what makes the analysis difficult is that an English court is only ever likely to think about these issues when the defendant is some or other arm of the British state. That being so, the likelihood of applying English domestic law – which seems to be quite keen to see the Human Rights Act come whomping down on the heads of those complained about – is high. What would be interesting would be to think how it would approach the problem if the state complained about were a foreign one. Then we should see the emergence of a real conflicts rule, as distinct from one almost preconditioned to point us to English law.

  4. Thank you, Adrian, for your insights. I agree that it would indeed be interesting to see how English courts would approach the problem if they had to determine the applicable law to assess the conduct of a foreign state. I think there are two possible scenarios here.
    The first scenario involves a foreign state as the defendant. Such scenario may not be far-fetched. There used to be a debate whether the territorial tort exception in the State Immunity Act 1978 applied only to ‘private torts’, such as traffic accidents, or also to torts arising out of the exercise of sovereign authority committed in the UK. Thanks to the actions of certain Middle Eastern countries engaged in spying on political dissidents by hacking their electronic devices in the UK, we now know that the territorial tort exception applies to both types of tort (Al-Masarir v Saudi Arabia [2022] EWHC 2199 (QB); Shehabi v Kingdom of Bahrain [2023] EWHC 89 (KB)). In these two cases, the courts have prioritised sovereignty concerns over comity, which perhaps indicates a preference for the application of English law.
    The second scenario involves a tortious claim against the UK government, alleging its complicity in an allegedly wrongful act or omission of a foreign state in a third state. Even if the former state is not a defendant, the courts may still have to determine the wrongfulness of its conduct in order to decide on the liability of the UK government. The first two rules of the foreign act of state doctrine would not apply here because the conduct in question is extraterritorial (Belhaj v Straw). Such a case would likely raise similar problems to those that arose in Zubayah.

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