UK Supreme Court finds that the “Crown act of state” doctrine bars certain international claims

Rahmatullah (No 2) v Ministry of Defence [2017] UKSC 1 (17 January 2017)


The UK Supreme Court unanimously held that the “Crown act of state” doctrine acts as a bar to certain claims against the Crown in the field of international affairs. The Court held that the doctrine comprises two elements: a rule of non-justiciability for certain acts committed by a sovereign state, and in narrowly confined circumstances, a defence to torts committed by the Crown against foreigners abroad.


Mr Rahmatullah, a Pakistani national, was captured by British forces in Iraq in February 2004. He was subsequently transported to a United States detention facility in Afghanistan, where he was detained until his release in May 2014. Mr Rahmatullah sued the Ministry of Defence and the Foreign and Commonwealth Office in respect of both his initial treatment by the British forces and the Government’s alleged complicity in his detention by the US. The first aspect of Mr Rahmatullah’s claim was based on the Iraqi law of tort and the Human Rights Act 1998 (UK). A large number of Iraqi citizens made similar claims in tort against the Government.

As a defence to the tort claims, the Government raised the doctrine of “Crown act of state”. The Government contended that the doctrine encompasses two distinct principles: a principle of non-justiciability for certain acts (such as declaring war or entering into treaties) and a defence to torts committed by the Government against foreigners abroad pursuant to deliberate foreign policy. The claimants submitted that the doctrine captures only the first principle, a narrow rule of non-justiciability. The issue before the Court was therefore the content and scope of the doctrine. Specifically, the Court was required to identify “the circumstances in which a claim is not cognisable in the courts of England and Wales because it relates to a ‘Crown act of state’”.


The Court unanimously held that the claimants’ detention by the British forces and their transfer to US custody were “Crown acts of state” for which the Government could not be liable in tort. The Court found that the doctrine comprises both a principle of non-justiciability and, in a narrowly confined class of “sovereign acts”, a defence to tort claims against the Government.

That the doctrine encompasses a rule of non-justiciability was not in dispute: as noted by all members of the Court, certain prerogative acts of the Crown in the sphere of foreign affairs – including entering into treaties, declaring war and conquering territories – are not subject to judicial review.

The leading judgment was delivered by Lady Hale, who found that the doctrine also encompassed a second distinct limb: a defence to tort claims against the Government for “inherently governmental” acts committed during military operations abroad. Yet she emphasised that the defence would be one of limited application, and would not confer a broad power on the Government to ratify any tortious conduct abroad. Of the class of acts to which the defence would apply, Lady Hale stated (at [37]):

We are left with a very narrow class of acts: in their nature sovereign acts – the sorts of thing that governments properly do; committed abroad; in the conduct of the foreign policy of the state; so closely connected to that policy to be necessary in pursuing it; and at least extending to the conduct of military operations which are themselves lawful in international law (which is not the same as saying that the acts themselves are necessarily authorised in international law).

Lord Mance, with whom Lord Hughes agreed, considered that the underlying principle of the doctrine is one of non-justiciability, and that to suggest that the doctrine encompasses two distinct limbs creates unnecessary confusion. This reservation notwithstanding, Lord Mance came to the same conclusion as Lady Hale: that the claimants’ detention by British forces and their transfer to US custody were “Crown acts of state.” This is because they were steps taken “pursuant to … deliberately formed policy” and in the “furtherance of military operations during a time of armed conflict” [75].

Lord Sumption agreed with Lady Hale that a limited class of acts constituting “Crown acts of state” gives rise to no liability on the part of the Crown or its agents, acting as a defence to tort claims. He found that the operation of the doctrine could be explained as a principle of coherence, as the use of armed force in military operations abroad involves acts which would normally be civil wrongs under English law. It would be “incoherent and irrational” for the courts to impose civil liability upon the Crown for acts done in the exercise of its lawful power to deploy force and conduct the United Kingdom’s foreign relations [88].

Finally, the Court held that the doctrine was not abolished by the Crown Proceedings Act 1947 (UK), and further, that the doctrine is compatible with the right to a fair trial protected by article 6 of the European Convention of Human Rights. This is because the doctrine is a substantive rule of law rather than a procedural bar, and does not prevent claimants from bringing actions against the Government.


The decision marks the most comprehensive judicial statement on the operation of the “Crown act of state” doctrine to date. In establishing that the doctrine may defeat claims brought against the UK Government by foreign citizens in respect of torts committed abroad, the decision will have significant ramifications for numerous ongoing cases that have arisen out of the UK’s intervention in Iraq and Afghanistan – and indeed, for any future tortious claims that may emerge in relation to the Government’s involvement in overseas military operations.

Yet the Supreme Court has elected to leave open a number of important questions regarding the doctrine’s precise scope. First, it remains unclear whether the doctrine would apply outside the context of military operations. Second, the Court did not decide whether the doctrine could be pleaded as a defence to claims brought by British citizens, merely noting that there are arguments “either way” in this respect. Finally, the judgment raises questions about the application of the doctrine in the (hypothetical) context of governmental torture and deliberate maltreatment of detainees in military operations. While Lady Hale suggested the doctrine would be inapplicable in cases of torture and maltreatment, this conclusion was based on the assumption that maltreatment of prisoners is not an inherently governmental act. As noted by Lord Sumption, it is possible – though improbable – that torture or maltreatment of detainees could be an act of state, done with the authority of the Crown. Lord Sumption suggests that if this were to occur, a decision by the UK Government to authorise torture would not be found to be a lawful exercise of the royal prerogative. However, if such an act by the executive was to be found lawful, it appears the “Crown act of state” doctrine could operate to bar claims in tort against the Government in respect of this maltreatment.

Elizabeth Brumby is an Assistant Editor of the Melbourne University Law Review and a Research Assistant at Melbourne Law School.