Strategic advice on investor–state disputes and treaty protections

Disputes involving states, state-owned entities and politically sensitive projects often raise issues that go beyond the contract. Our public international law team advises investors, businesses and institutions on complex disputes involving treaties, sovereign states, and cross-border frameworks.

We provide strategic advice on treaty interpretation and treaty-based protections, including bilateral investment treaties (BITs) and multilateral investment protection frameworks, as well as jurisdiction and admissibility, sovereign immunities and enforcement strategy.

Our public international law capability sits within our wider international disputes and arbitration practice, allowing us to coordinate arbitration proceedings with related litigation and enforcement actions across multiple jurisdictions.

Meet the Public International Law Team

Investor–state arbitration and treaty disputes

We act for investors in investor-state arbitration proceedings under a range of institutional and treaty frameworks, including:

  • International Centre for Settlement of Investment Disputes (ICSID)
  • International Chamber of Commerce (ICC)
  • UNCITRAL Arbitration Rules
  • USMCA investment arbitration proceedings

Our experience spans disputes across a range of sectors including natural resources, mining and strategic infrastructure projects.

We advise clients throughout the full lifecycle of a dispute, including:

  • investment structuring and treaty protection analysis
  • jurisdiction and admissibility challenges
  • merits and liability phases
  • quantum and damages assessment
  • annulment proceedings
  • enforcement of arbitral awards across jurisdictions

Experience on both sides of investor–state disputes

Our team brings experience advising both investors and state entities, providing valuable insight into how investor–state disputes are assessed, defended and resolved.

Marta Grieve has represented governments and state-owned entities in high-value ICSID proceedings, giving her a clear understanding of how states assess risk, frame jurisdictional objections and approach settlement, an advantage she now brings to bear when acting for investors.

Jan Kunstyr has acted for investors in ICSID, UNCITRAL, USMCA and ICC proceedings and holds an LL.M. in Investment Treaty Arbitration.

Together, they combine doctrinal rigour with practical disputes experience, and are used to advising on matters where legal analysis and political or regulatory context run in parallel.

We also support clients, including public bodies and international organisations, where legal strategy needs to investment structuring and future proofing taking into context investment protection and tax structure.