CA-2024-002080 - [2025] EWCA Civ 905

As the Judge recognised, the Treaty is to be interpreted in accordance with the principles set out in the VCLT, reflecting customary international law. The whole point and purpose and effect of the Treaty is that that approach to interpretation is to be applied equally and uniformly by the courts of all signatory jurisdictions, including the courts of England and Wales, it being plainly desirable that a treaty is interpreted consistently across jurisdictions. As Lord Hope stated in Islam v Secretary of State for the Home Department [1999] 2 AC 629, 657A-B:

“As a general rule it is desirable that international treaties should be interpreted by the courts of all the states uniformly. So, if it could be said that a uniform interpretation of this phrase was to be found in the authorities, I would regard it as appropriate that we should follow it.”

It is therefore unclear what scope there is for the English court to consider issues of national policy, as suggested by the Judge at [28], when considering whether and to what extent a treaty, on its proper interpretation, imposes conditions on a State’s offer to arbitrate a dispute so as to give rise to a valid arbitration agreement. Whilst that may give rise to an issue as to whether the arbitral tribunal has substantive jurisdiction by virtue of English domestic legislation (section 30 of the 1996 Act), the answer to the treaty interpretation question is a matter of international law and must be the same (or at least approached in the same way) whether being determined by an ITA tribunal or the English court. In my judgment, and as submitted by Korea, there is no basis on which the English court can or should factor into its interpretation of an international treaty the fact that one of two competing interpretations would engage “the ability to re-argue on a de novo basis before a municipal court issues relating to the application of an international law treaty, and to set aside or declare of no effect the determination of an international tribunal”. I note that this Court in The Czech Republic v Diag Human SE [2025] EWCA Civ 588 has recently expressed the view at [130] that the “caution” expressed by the Judge at [28] in his judgment in this case was well-founded, but I understand that to refer to the Judge’s point that caution may be needed in reading what ITA tribunals decide about jurisdiction as they may be less concerned about distinguishing between jurisdiction, standing and admissibility. I do not read it as approval of the Judge’s invocation of national policy in interpreting an international treaty. Indeed, in Diag this Court emphasised at [125] and [128] that the question of whether there was an offer to arbitrate in a BIT was ultimately a question of interpretation of the Treaty in accordance with the principles in Article 31 of the VCLT.

Further, given the approach of Articles 31 and 32 of the VCLT, starting with the ordinary meaning to be given to the terms of the treaty in question, in their context and in light of its object and purpose, I do not accept that it is relevant to draw “principles” from English authorities as to whether particular issues “will be jurisdictional for section 67 purposes”, or to suggest that so categorising an issue will give rise to a “greater challenge”, “may be more difficult in the absence of express language” or “may suggest that the issue is not jurisdictional” (judgment at [37]).

The sole question of interpretation engaged in this case is whether, applying the straightforward approach to interpretation set out in the VCLT, the satisfaction of the requirements of Article 11.1(1) is a condition of Korea’s offer to arbitrate. There is no suggestion that, in drafting the relevant provisions, Korea and the USA had in mind English domestic law as to jurisdictional challenges to arbitration awards, and there is therefore no basis for importing and applying “rules” of construction or presumptions drawn from a collection of first instance decisions of the English courts.

I would therefore uphold Korea’s first subsidiary criticism of the Judge’s approach. To what extent the principles of interpretation identified by the Judge at [37] (wrongly, in my judgment) affected his ultimate conclusion is unclear: his analysis focused closely on the meaning of the provisions of the Treaty, and in particular Chapter 11, to which I shall now turn.