Janssen-Cilag Limited v The United States of America

Section 12(7) of the State Immunity Act 1978 excludes only a true action in rem, commenced by service on the res, such as an Admiralty action against a ship or cargo. A patent revocation claim is instead an action in personam against the proprietor, even though revocation has effect in rem against the world. A foreign State may agree under section 12(6) to service by an alternative method. Providing an unrestricted United Kingdom address for service for a registered patent objectively constituted such agreement. Where section 12(1) applies, the court has no power under CPR 6.15 to authorise alternative service.

Janssen-Cilag Limited sought revocation of a European patent (UK) registered in the name of the United States of America, represented by the Department of Health and Human Services. The United States applied to set aside service of the revocation proceedings.

The claim had been served at an address for service entered on the UK Intellectual Property Office register. The United States also challenged earlier orders permitting alternative service, contending that section 12(1) of the State Immunity Act 1978 required diplomatic service. The central issues were whether service at the registered address was agreed service under section 12(6), and whether patent revocation proceedings were an action in rem within section 12(7).

1. Service under section 12(6). The United States had been validly served when the claim and accompanying documents were served at the London address for service registered for the patent. Whether a State has agreed to a method of service is determined objectively. Section 12(6) imposes no formal requirements, and agreement may arise through writing, speech or conduct. The United States had voluntarily provided the unrestricted address, through its governmental department and patent representatives, knowing that CPR 63.14 permitted service of proceedings concerning the registered right at that address.
2. The asserted purposes of validating the European patent and the alleged lack of authority were rejected. The address was not required for validation, and no sufficient evidence established that the relevant United States governmental department lacked authority. The provision of the address did not amount to submission to jurisdiction under section 2; it was agreement to a method of service.
3. Section 12(7). The phrase “an action in rem” refers to a true action in rem in which proceedings are commenced by service on the res. The two exclusions in section 12(7) concern circumstances where service on the State is unnecessary: a counterclaim follows the State’s submission by bringing proceedings, while an action in rem is commenced by service on the relevant res.
4. A patent revocation claim is not such an action. Although a patent is a res and revocation produces a decision having effect against the world, the claim is commenced against the proprietor and does not require service on, arrest of or security over the patent. An action in personam may therefore produce a decision in rem without becoming an action in rem.
5. Section 12(1) consequently applied when HHJ Hacon made the earlier orders. The court had no discretion under CPR 6.15 to authorise alternative service where section 12(1) applied. The orders for alternative service were made without power, although the service at the registered address was valid under section 12(6).
6. The question of the correctness of the wider statement in Dicey, Morris & Collins concerning Admiralty claims was left undecided. The outstanding application for expedition was to be heard with consequential matters.

First-instance decision. The judgment records earlier service orders made by HHJ Hacon on 25 February and 4 March 2026, but no appeal from those orders.