In December 2012 the applicant, the Attorney-General of Ghana applied for orders of certoriari and prohibition against the High Court of Ghana, which had ordered the detention of the Argentinian warship ARA Libertad and had refused to set aside that order. The judge held that the High Court had jurisdiction to arrest the Argentinian warship since the Republic of Argentina had contractually waived its sovereign immunity.

In October 2012 Argentina submitted its dispute with Ghana over the detention of the ARA Libertad to arbitration under Annex VII of the United Nations Convention on the Law of the Sea 1982 (UNCLOS). Pending the decision of the arbitration tribunal, Argentina requested the prescription of provisional measures from the International Tribunal for the Law of the Sea (ITLOS). The release of the ARA Libertad was ordered by ITLOS on 15 December 2012 (see The 'Ara Libertad' Case (Argentina v Ghana) (CMI458)).

In applying for the certoriari and prohibition orders, the applicant sought to enable Ghana to comply with its international obligations, in particular the ITLOS order. He argued, amongst other things, that the High Court had erred in international law by finding that the immunity of warships could be waived, maintaining that UNCLOS was incorporated into Ghanaian law by art 75 of the 1992 Constitution.

Held: The application for an order of certiorari is granted. The application for an order of prohibition is denied.

In relation to UNCLOS, there has been no incorporation of its provisions into Ghanaian municipal law, except to a limited extent in the Maritime Zones (Delimitation) Act 1986. Where the actions of national courts attract delictual or contractual responsibility for a State on the international law plane, the most effective remedial measure will usually be the enactment of national legislation. Without prejudice to the merits of this present application, this approach is urged on the Government of Ghana in relation to its obligations under UNCLOS. It should be mentioned, though, that some of the provisions of UNCLOS have become customary international law through the practice of States. Such customary public international law would, of course, be given effect in Ghanaian law as part of the common law of Ghana.

The second ground relied on by the Attorney-General is that the High Court wrongly assumed jurisdiction in this case by putting an incorrect interpretation on a clause by which Argentina is alleged to have waived its sovereign immunity. This ground is upheld. Although Argentina waived its immunity through the contractual waiver clause, that waiver of immunity is not binding on the Ghanaian courts in so far as it relates to a military asset. Customary international law permits sovereign States to decide whether to accord a wider immunity in their municipal law than required under international law. There is thus no obligation in municipal law to recognise waivers of sovereign State immunity in all circumstances, except those required by public international law.

The trial judge, who was not bound by any previous decided Ghanaian case on this issue, made a fundamentally and patently wrong decision by holding that Argentina’s contractual waiver of immunity, in so far as it related to the seizure of a military asset, should be given effect to. The courts of Ghana ought not to promote conditions leading to possible military conflict, when they have the judicial discretion to follow an alternative path. This public policy consideration persuades the court that waiver of sovereign State immunity over military assets should not be recognised under Ghanaian common law.

With this clarification of the law by the court, there should be no need for any order of prohibition to be issued. All lower courts are obliged to follow and apply the law as clarified in this case. There should accordingly be no further seizures of military assets of sovereign states by Ghanaian courts in execution of foreign judgments, even if the sovereign concerned has waived its immunity.