‘A top set with excellent practitioners both senior and junior’, members of 3 Verulam Buildings integrate expertise in international commercial law and treaty arbitration to lead on international law matters concerning the obligations of states, international organizations, and corporations. Prominent individuals lead in English and international courts alike; Christopher Harris KC, ‘undoubtedly one of the leading silks at the bar in this area’, led when acting for the claimant in Zhongshan Fucheng v Nigeria, which concerned the interplay between states’ rights to immunity under international law and English procedural laws. Leading juniors include international treaty arbitration specialist Cameron Miles, who has ongoing involvement in proceedings for Pakistan concerning the Indus Water Treaty; and the ‘highly practical and commercially attuned’ Mark Wassouf who continues to act as lead junior counsel for the Russian Federation in the Court of Appeal concerning its defence of attempts to enforce the arbitral award against it concerning the expropriation of Yukos.

With ‘terrific capability and expertise at all years of call’, Essex Court Chambers continues to lead in public international law, with members appearing in high-profile cases before the ICJ, ITLOS and a range of domestic courts. The ‘unfailingly polite, respectful and cogent’ Sam Wordsworth KC recently defended the Government of Azerbaijan in ICJ cases against Armenia, in which both states accuse each other of violating the International Convention on the Elimination of All Forms of Racial Discrimination. At the junior level the set includes the ‘phenomenally clever’ Sean Aughey who has acted on behalf of Iran concerning the legality of US sanctions under international law. ‘Precise and compelling’, Tariq Baloch KC joined the Chambers in 2024 and is highly prominent in international treaty arbitration cases, with recent success representing Spain in the Court of Appeal concerning the registration of a €120m ICSID award against it. Hugh Mercer KC is now the British judge on the European Court of Human Rights.

‘A go-to set for any international matter’, Twenty Essex‘s public international law expertise covers disputes between states, non-state actors, major investors, and global commercial bodies in an array of international courts and tribunals. Daniel Bethlehem KC has continued long-term involvement on behalf of Pakistan in a dispute with India concerning the Indus Waters Treaty dispute, with a recent full hearing on merits in the Permanent Court of Arbitration, and Sudhanshu Swaroop KC, praised for his ‘top notch attention to detail, precision and concision’, acted for India in Devas Mauritius Ltd & Ors v Republic of India, challenging the enforcement of a major international investment treaty in English courts. The ‘highly authoritative’ Kate Parlett has expertise in investment treaty arbitration, and acted on behalf of investors in the Court of Appeal in The Czech Republic v Diag Human SE and Stava, concerning an investment treaty arbitral award of over $730 million.

‘Very professional and rightly highly regarded’, Brick Court Chambers remain active in international disputes and arbitrations involving states, private entities, and investors. The set’s members are regularly instructed by prominent charities and NGOs in public international matters. Edward Ho has ongoing involvement representing the claimant in Naftogaz vs the Russian Federation, which concerns the enforcement of arbitration awards worth over $4 billion which involves arguments of state immunity under international law, and ‘intellectual powerhouse‘ Maya Lester KC has a broad public law practice, with recent work including representing the applicant in a public law challenge to the FCDO’s decision to sanction a Belarusian company.

Members of Blackstone Chambers lead on a variety of public international law matters, often integrating established practices in international human rights, European Union law, and investment treaty arbitration in cases in domestic and international courts. With depth at the silk level, the ‘highly polished and impressive’ Timothy Otty KC has continued involvement as lead counsel in Ukraine’s interstate damages case against Russia before the ECHR, and Jason Pobjoy KC and Naina Patel KC both took silk in 2025, each of whom has an established and high-profile public international law practice: Pobjoy KC acted for the UK Government in the ICJ on the advisory opinion in relation to climate change. ‘First class, technically brilliant’, Paul Luckhurst acted for the lead defendants in Hashwah & ors v Qatar National Bank & ors, a case which concerned the state immunity of Qatari individuals and financial institutions.

Matrix Chambers has a breadth of public international law experience and expertise, spanning from territorial disputes between states, arbitration award enforcement, and the provision of advisory opinions in major international courts and tribunals. A ‘compelling advocate and creative legal thinker’, Edward Craven KC took silk in 2025, and has ongoing involvement acting for Guyana in provisional measures before the ICJ concerning Venezuela’s attempts to claim sovereignty over (and threats to invade) the Essequibo region – over two-thirds of the country’s territory and with significant energy resources – citing allegations of corruption in a 1899 arbitral award.