Private International Law Bonanza in the UK Supreme Court

On 27 July 2026, the UK Supreme Court released three judgments of relevance for private international law, thereby providing a lot of interesting material to read over the summer. Collectively, the three judgments concern state immunity, jurisdiction and the effects of foreign judgments.

This post briefly outlines the facts, issues and decisions in these three cases.

The Kingdom of Bahrain v Shehabi [2026] UKSC 25 (on the “territorial tort exception” to state immunity)

Section 1 of the State Immunity Act 1978 affords general immunity to foreign states from the jurisdiction of UK courts, save as provided for in the exceptions given in sections 2 to 11 of the Act. Section 5 lays down the “territorial tort exception”, which applies “as respects proceedings in respect of death or personal injury or damage to or loss of tangible property, caused by an act or omission in the United Kingdom”.

It was assumed for the purposes of the appeal that Bahrain’s servants or agents, who were likely operating remotely from outside the UK using a server located in Bahrain, hacked the computers of two British-based pro-human rights and democracy activists with spyware, in the circumstances where both the activists and their computers were in the UK at the relevant times. The activists brought proceedings against Bahrain, alleging that the hacking and spying involved a course of conduct amounting to harassment, contrary to the Protection from Harassment Act 1997.

The question was whether the territorial tort exception applied.

The Supreme Court answered the question in the affirmative by 3:2 (Lord Lloyd-Jones, Lord Hamblen and Lady Simler gave the majority judgment; Lord Leggatt and Lord Burrows dissented). The territorial tort exception did not require every legally causative act (or omission) to be in the UK; did not require the legally causative act(s) in the UK relied on by a claimant to be the initiating, precipitating or responsible act(s); did not require the presence of the responsible actor in the UK at the time of the act(s); and did not draw any distinction between sovereign and non-sovereign acts. The decision is particularly important because it confirms that automated or remotely conducted cyber operations may constitute acts in the UK for the purposes of section 5 of the 1978 Act.

Tesla, Inc v InterDigital Patent Holdings, Inc [2026] UKSC 27 (on jurisdiction in FRAND disputes between implementors and owners of standard essential patents)

This case concerned service out of the jurisdiction with the permission of the court.

This case involved a dispute between Tesla US and Tesla UK, on the one hand, and InterDigital Patent Holdings, Inc, InterDigital Holdings, Inc and Avanci Vehicle, LLC, all Delaware corporations, on the other hand. The InterDigital group owned a worldwide portfolio of Standard Essential Patents (“SEP”) for the European Telecommunications Standards Institute 2G, 3G, 4G and 5G standards, including, through InterDigital Patent Holdings, Inc, certain UK patents relevant to the 5G standard which Tesla wished to implement. Avanci administered a global platform for the licensing of 2G, 3G, 4G and 5G SEPs for use in connection with 5G-enabled vehicles. InterDigital was one of the SEP owners on the Avanci 5G platform as licensors. Tesla sought multiple declarations that, amongst other things, they were entitled to a fair, reasonable and non-discriminatory (“FRAND”) licence to all SEPs on the platform and that the current platform fee is not FRAND.

The question was whether English courts had jurisdiction to determine the Licencing Claims. The answer to that question depended on whether:

(1) there was a serious issue to be tried on the Licencing Claims;

(2) the Licencing Claims against InterDigital Patent Holdings, Inc were properly served pursuant to CPR r 63.14(2);

(3) the Licencing Claims against InterDigital Holdings, Inc passed through either the necessary or proper party gateway in CPR Practice Direction 6B, para 3.1(3) or the property gateway in para 3.1(11); and

(4) whether England was the proper forum.

Lord Briggs and Lord Hamblen gave the judgment, with whom Lord Sales, Lord Stephens and Lord Doherty agreed.

Question (1) was a matter of substantive law, which the Supreme Court answered in the affirmative.

The Supreme Court also answered question (2) in the affirmative, based on the wording of CPR r 63.14(2), which allows for service of “a claim form relating to a registered right … on a party who has registered the right at the address for service given for that right in the appropriate register at … the UK Patent Office”. Since InterDigital Patent Holdings, Inc was the owner of the UK SEPs on the Avanci 5G platform and the Licencing Claims related to those registered rights, they were properly served on this defendant within the jurisdiction.

Answering question (3) required interpretation of the two gateways. The Supreme Court held that they were both satisfied. InterDigital Holdings, Inc was a necessary or proper party. The Licencing Claims related wholly or principally to property in the UK, namely UK patents, notwithstanding that the declarations sought concerned the terms of a worldwide FRAND licence.

Finally, the answer to question (4) depended on the proper characterisation of the Licencing Claims. These claims were about the licensing of InterDigital’s UK SEPs on the Avanci 5G Platform and what terms for a licence of those UK SEPs were FRAND. The Supreme Court held that the Delaware Court of Chancery was not an available forum for the claims as properly characterised because it would not adjudicate FRAND terms for non-US patents, such as the UK SEPs. Accordingly, the forum challenge failed.

Drelle v Servis-Terminal LLC (In Liquidation in the Russian Federation) [2026] UKSC 29 (on whether an unrecognised foreign judgment is a “debt” for the purposes of a bankruptcy petition)

For a creditor to present a bankruptcy petition against a debtor, section 267 of the Insolvency Act 1986 requires, among other pre-conditions, that the petition is in respect of one or more “debts” owed by the debtor to the petitioning creditor.

The question in this case was whether the creditor of a Russian judgment for a debt or definite sum of money might rely on it as the basis for being owed a debt, sufficient to commence bankruptcy proceedings, in the circumstances where the judgment had not been made the subject of recognition proceedings in the UK.

Lord Briggs and Lord Hamblen gave the judgment, with whom Lord Sales, Lord Stephens and Lord Doherty agreed.

The Supreme Court answered this question in the affirmative. The court reaffirmed the common law “obligation principle”, according to which a foreign judgment for a debt or definite sum of money gives rise to an obligation to pay the sum for which judgment has been given. That obligation arises when the final and conclusive judgment is given. It does not depend upon recognition. The unrecognised Russian judgment (which  was assumed for the purposes of the appeal to have been given by a court of competent jurisdiction, final and conclusive, for a debt or definite sum of money and unimpeachable) gave rise to an immediate legal obligation at common law to pay the relevant sum. The court held that this common law effect was sufficient for the judgment debt to constitute a “debt” for the purposes of bankruptcy proceedings, even though the foreign judgment had not yet been recognised by an English court.

Taken together, the three judgments address two pillars of private international law: jurisdiction (including state immunity) and foreign judgments. They continue the development of England as a leading global dispute resolution centre and illustrate the increasingly expansive approach of English courts to jurisdiction in international litigation.