A series of 2024–2026 rulings has crystallised a two-track approach to sovereign immunity as a defence against the enforcement of investor-State arbitral awards. Where an award is issued under the ICSID Convention, courts in England and Wales and in Singapore have treated a State's ratification of the Convention as a clear waiver of jurisdictional immunity. Where enforcement proceeds under the New York Convention (NYC), the outcome now turns on the domestic law of the enforcing forum—and courts have reached opposing conclusions.
ICSID awards: immunity gives way to enforcement
In 2024 the UK Supreme Court, deciding combined appeals in The Kingdom of Spain v Infrastructure Services Luxembourg S.à r.l. and Republic of Zimbabwe v Border Timbers Ltd, held that a State's accession to the ICSID Convention amounts to a waiver of jurisdictional immunity for recognition and enforcement. The Court found that Article 54(1)—which requires each Contracting State to recognise and enforce ICSID awards as domestic judgments—is incompatible with a State retaining immunity, and constituted "a clear and unequivocal submission" to the jurisdiction of the English courts under Section 2(2) of the State Immunity Act 1978. No "magic words" such as "waiver" were required.
In 2026, the Singapore High Court reached the same result in NextEra Energy v Kingdom of Spain, holding that Spain's accession to the ICSID Convention amounted to an express submission to jurisdiction under Section 4(2) of the Singapore State Immunity Act 1979. The court went a step further than the UK Supreme Court, finding that Spain and the investors had also entered into a valid arbitration agreement under Section 11 of the Act, given that the Energy Charter Treaty contained a standing offer to arbitrate accepted when the investors commenced proceedings. That reasoning aligns Singapore with earlier decisions in England and Wales and with the Quebec Court of Appeal.
New York Convention awards: no uniform answer
The NYC is silent on sovereign immunity, leaving the question to domestic law. Enforcement of the UNCITRAL award in CC/Devas et al. v The Republic of India, administered by the Permanent Court of Arbitration, has produced divergent outcomes across jurisdictions:
- Canada — The Quebec Court of Appeal held in 2024 that India's entry into the relevant bilateral investment treaty, its ratification of the NYC and its participation in the arbitration together amounted to an express waiver of jurisdictional immunity. The Supreme Court of Canada denied leave to appeal in September 2025.
- Australia — The Full Federal Court found in January 2025 that the award fell outside India's "commercial" reservation and that ratifying the NYC did not waive immunity. In April 2026 the High Court of Australia dismissed the appeal, holding that Article III of the NYC preserves forum procedural rules, including immunity, and that no analogy could be drawn with the ICSID Convention.
- England and Wales — The High Court held in April 2025 that ratification of the NYC did not waive immunity, construing any waiver restrictively against the State. The Court of Appeal affirmed in June 2026, applying reasoning consistent with the Australian High Court and finding that Article III preserved sovereign immunity.
Why it matters
The rulings confirm that the enforcement framework materially affects an award creditor's prospects. ICSID awards enjoy a comparatively predictable, creditor-friendly regime, while immunity defences to NYC enforcement depend entirely on the law of the enforcing forum. For investors, the divergence underscores the need to assess the immunity landscape of likely enforcement jurisdictions before pursuing recovery against States.