05/03/2026

State immunity is no bar to the registration of ICSID awards

The Supreme Court has unanimously held, in linked appeals, that Spain and Zimbabwe have submitted to the jurisdiction of the English courts under s.2(2) of the State Immunity Act (SIA) by virtue of article 54(1) of the ICSID Convention, and therefore may not rely on state immunity to oppose the registration of ICSID awards against them.

The judgment in The Kingdom of Spain v Infrastructure Services Luxembourg S.À.R.L. and another; Republic of Zimbabwe v Border Timbers Ltd and another [2026] UKSC 9 clarifies the effect of art 54(1) of the ICSID Convention on immunity from adjudicative jurisdiction. It also casts welcome light on the ratio of the complex and overlapping judgments in R v Bow Street Magistrate, Ex parte Pinochet (No 3) [2000] 1 AC 147 (Pinochet (No 3)).

Professor Philippa Webb represented the first respondent in the appeal, Infrastructure Services.

Infrastructure Services attempted to have an ICSID award of over €100 million against Spain registered as a judgment of the English court under s.1(2) of the Arbitration (International Investment Disputes) Act 1966. Spain resisted those attempts, on the basis that it was immune from the adjudicative jurisdiction of the English courts under s.1(1) SIA. Spain’s application to set aside was dismissed by Fraser J. Spain’s appeal was heard and dismissed by the Court of Appeal.

The requirements of waiver

Art 54(1) of the ICSID Convention provides:

“Each Contracting State shall recognize an award rendered pursuant to this Convention as binding and enforce the pecuniary obligations imposed by that award within its territories as if it were a final judgment of a court in that State. A Contracting State with a federal constitution may enforce such an award in or through its federal courts and may provide that such courts shall treat the award as if it were a final judgment of the courts of a constituent state.”

As the Supreme Court judgment noted: “A considerable amount of time was devoted at the hearing to the question whether any waiver of immunity by treaty must be express or whether it may be implied” [43]. Do the words “waiver”, “submission” or “immunity” have to be used in an agreement for a State to submit to the jurisdiction under s.2 SIA? The court answered in the negative. Section 2(2) SIA does not use the terminology of express or implied submission or waiver; it “simply states that a state may submit after a dispute giving rise to the proceedings has arisen or by prior written agreement” [45].

In defining the requirements for waiver, the court paid close attention to Pinochet (No 3). In that case, the key question was whether the states parties to the 1984 Convention against Torture had agreed to exclude reliance on immunity ratione materiae for proceedings for alleged torture brought against their public officials, or other persons acting in an official capacity.

Spain had relied on the dissenting judgment of Lord Goff in Pinochet (No 3). The Supreme Court engaged in extensive analysis of the reasoning of the other six members of the Appellate Committee in order to identify the ratio [70]:

“We consider that the ratio of Pinochet (No 3) is that, as between states party to the Convention against Torture, that Convention excludes the operation of immunity ratione materiae. Four of the Law Lords (Lord Browne-Wilkinson at 205C-F; Lord Saville of Newdigate at 266D, 266H-277B, 267F-G; Lord Millett at 277D-E, 277H-278B; Lord Phillips of Worth Matravers at 290E-G) considered that, since the offence of torture established by the Convention is limited to offences of torture committed in an official capacity, every case would otherwise be met by a plea of immunity. The immunity would be exactly coextensive with the offence. In these circumstances the parties to the Convention against Torture must be taken to have decided that immunity ratione materiae should not be available.”

The court went on to note that in another respect, the case at hand was “stronger than Pinochet (No 3)” [117]. While the Convention against Torture required each contracting state to make torture an offence in domestic criminal law, to establish jurisdiction over such offences in certain circumstances, and to extradite or prosecute an alleged perpetrator found on its territory, the national authorities have a discretion as to whether or not to exercise the jurisdiction. By contrast, the obligation under art 54(1) of ICSID is an obligation of result: to recognise an award as binding and to “enforce the pecuniary obligations imposed by that award within its territories as if it were a final judgment of a court in that State”. The obligation to treat an ICSID award “the final product of the judicial process, is entirely incompatible with immunity from that judicial process”.

This case is the latest in a series of cases around the world to consider this issue of waiver of adjudicative immunity (Australia, New Zealand, Malaysia, the United States and the British Virgin Islands). It is a significant judgment of the Supreme Court interpreting the ICSID Convention, which has 158 contracting states.

Philippa Webb represented the first respondent with Patrick Green KC, Andrew Stafford KC and Richard Clarke. She was instructed by Kobre & Kim.