The Secretary of State for Foreign and Commonwealth Affairs and the Secretary of State for Defence were not required to hold a public inquiry or similar investigation into the killing, by British soldiers on patrol, of 24 unarmed civilians in 1948 in the State of Selangor, then a British protected state in Malaya.

The Supreme Court so held (Baroness Hale of Richmond DPSC dissenting) when dismissing an appeal by the claimants, Chong Nyok Keyu, Loh Ah Choi, Lim Kok and Wooi Kum Thai from the Court of Appeal (Maurice Kay, Rimer and Fulford LJJ) [2015] QB 57; [2014] WLR (D) 138 on 19 March 2014 to dismiss their appeal against the decision of a Divisional Court of the Queen’s Bench Division (Sir John Thomas P and Treacy J) [2012] EWHC 2445 (Admin); [2012] WLR (D) 261 which on 4 September 2012 had dismissed their challenge to the decisions of the Secretaries of State, dated 29 November 2010 and confirmed on 4 November 2011, that in their discretion they would not hold a public inquiry or any other investigation into the killing of 24 civilians by a patrol of the Scots Guards in 1948 at the village of Batang Kali in the State of Selangor, at that time a protected British State, and now part of Malaysia.

The claimants, who were relatives of the deceased, contended that a public inquiry was required (i) under article 2 of the European Convention for the Protection of Human Rights and Fundamental Freedoms, which had come into force in 1953 and had been extended in that year to the Federation of Malaya; (ii) under the common law by virtue of its incorporation of principles of customary international law; and (iii) under the common law through the medium of judicial review.

LORD NEUBERGER OF ABBOTSBURY PSC, with whom LORD HUGHES JSC agreed, referring to the first ground, said that the law relating to the duty to investigate suspicious deaths as interpreted by the European Court of Human Rights had been developed importantly, in particular, in the Grand Chamber decisions of Šilih v Slovenia (2009) 49 EHRR 996 and Janowiec v Russia (2013) 58 EHRR 792. Thus the duty to investigate had evolved into an autonomous, detachable obligation on the state, capable of binding it even when the death had taken place before the date when the particular state subscribed to the Convention. Although the Convention was not retrospective, that did not necessarily mean that no such investigative duty arose where a suspicious death had occurred before “the critical date”. In such a case two criteria had to be satisfied before the duty could arise: there had to be (1) relevant acts or omissions after “the critical date” and (2) a genuine connection, not exceeding 10 years, between the death and “the critical date”. The second criterion might be finessed where it was necessary to underpin the underlying Convention values. The claimants satisfied the first criterion: prior to 1970 there had been no full or public investigation of the killings; until 1969 there had been no publicly available evidence from any member of the patrol to suggest that the killings had been unlawful; the evidence which had first come to light in 1969 and 1970 plainly suggested that that was so, and, although not conclusive, it was weighty and compelling. Whether there was a genuine connection exceeding the 10 year run back depended on whether the critical date was the date of the coming into force of the Convention with respect to the United Kingdom in 1953, as the claimants contended, or the date when an individual’s right of petition was recognised, in 1966, as suggested by a number of cases in the European Court of Human Rights. In his Lordship’s judgment, it was the latter date. Apart from the European Court of Human Rights jurisprudence, that accorded better with principle. The “rule” was substantially based on practicalities; it was a topic on which clarity and consistency was highly desirable, and, unless the European Court of Human Rights guidance seemed unclear, incoherent or unworkable, it was an area in which the domestic court should follow the European Court of Human Rights. The second criterion, of genuine connection, was not therefore met. Since a contracting party could not be held responsible for not investigating even the most serious crimes under international law if they predated the Convention (see the Janowiec case), finessing the second criterion could not assist the claimants. It followed that in so far as the claim was based on article 2, it failed; the European Court of Human Rights would rule it inadmissible since the killings had taken place more than 10 years before United Kingdom citizens had the right of petition.

On the second ground of appeal, customary international law could not be invoked to require the United Kingdom Government to investigate the killings: in the first place, it was not established that international law in 1948 had developed to the extent of requiring a formal public investigation into suspicious deaths even if there were strong reasons for believing that they constituted a war crime; and secondly, even if international law required such an investigation, the requirement could not be implied into the common law. Parliament had expressly provided for investigations into deaths through the coroners’ courts in the Coroners and Justices Act 2009, and its predecessors, and through inquiries in the 2005 Act and its subject-specific predecessor statutes. Parliament had also effectively legislated in relation to suspicious deaths through the incorporation of article 2 by the Human Rights Act 1998. In those circumstances it was inappropriate for the courts to take it onto themselves, through the guise of developing the common law, to impose a further duty to hold an inquiry, particularly when it would be a duty which had such potentially wide and uncertain ramifications.

The third ground, based on common law, namely, the claimants’ challenge by way of judicial review, as a matter of the Secretaries of State’s discretion, not to order an inquiry under the 2005 Act, also failed. The normal principle was that an executive decision could only be overruled by the court if it had been made in excess of jurisdiction or effected for an improper purpose, or was irrational in the sense discussed in Associated Provincial Picture Houses Ltd v Wednesbury Corpn [1948] 1 KB 223. The argument on Wednesbury grounds failed, substantially on the basis of the analysis adopted by the Court of Appeal. The Secretaries of State had considered the request for an inquiry seriously and rejected it for defensible reasons which cumulatively rendered it impossible to characterise the decision as irrational. There was no suggestion that it was tainted in any other way and, accordingly, applying classic judicial review principles, it could not be impugned.

The claimants argued that the traditional rationality basis for challenging executive decisions should be replaced in domestic judicial review cases by a more structured and principled challenge based on proportionality, applying the four-stage test identified by Lord Sumption and Lord Reed JJSC in Bank Mellat v HM Treasury (No 2) [2014] AC 700, paras 20, 74. However, it would not be appropriate for a five-judge panel either to accept or reject that argument. It had potentially profound constitutional implications and was very wide in applicable scope. The court would become involved in considering the merits of the decision at issue and, although it would not replace the relevant member of the executive as the primary decision-maker, it would be required to assess the balance that decision-maker had struck between the competing interests. It might be that domestic law was already moving away to some extent from an irrationality test in some cases, and that the court’s approach might depend on the nature of the issue. In the present case the Secretaries of States’ decisions had been neither irrational nor disproportionate.

LORD MANCE, delivering a judgment concurring with Lord Neuberger of Abbotsbury PSC and with which LORD NEUBERGER OF ABBOTSBURY PSC, LORD KERR OF TONAGHMORE and LORD HUGHES JJSC agreed, examined the question whether the claimants’ complaint related to alleged failures of the United Kingdom to “secure to everyone within its jurisdiction” within the meaning of article 1 of the Convention any of the rights and freedoms defined in article 2, so as to make the United Kingdom potentially responsible for breach of the Convention as incorporated into domestic law by the Human Rights Act 1998. He concluded that, had the other conditions for ordering an inquiry been satisfied, there would be no jurisdictional obstacle to doing so.

LORD KERR OF TONAGHMORE JSC delivered a judgment concurring in the result.

BARONESS HALE OF RICHMOND DPSC delivered a judgment dissenting in the result.