Guglielmo Verdirame KC > Twenty Essex > London, England > Lawyer Profile

Twenty Essex

Work Department

  • Constitutional public and human rights law
  • Energy and natural resources
  • International arbitration
  • Public international law


Lord Verdirame KC specialises in public international law, international arbitration (especially investment treaty arbitration and inter-state arbitration), human rights and constitutional law. His practice covers the full range of public international law including international dispute resolution; immunities; foreign investment protection; law of the sea; territorial and maritime boundary disputes; status of territories; human rights; use of force; law of armed conflict; international organisations; sanctions; trade.

Guglielmo has acted as counsel in many high-profile cases before international courts and tribunals, including before the ICJ, ITLOS, Annex VII Tribunal under UNCLOS. He was counsel for the UK in the last dispute to be brought against the UK in the International Court of Justice (Marshall Islands v UK), and for the Italian Republic in the Enrica Lexie Incident dispute before both the UN Tribunal for the Law of the Sea and the arbitral tribunal in the Permanent Court of Arbitration. He is currently instructed for Ukraine in the case against Russia arising from the recent conflict in the European Court of Human Rights.

Guglielmo has also been instructed in some of the highest-level litigation involving international law issues in the English courts. Before the Supreme Court, he was counsel for the government in the first Miller case on the UK’s withdrawal from the European Union, and for the UN special rapporteur on counter-terrorism and human rights in the Shamima Begum case. He has recently acted for Princess Haya of Jordan in the widely reported proceedings between her and the Prime Minister of the UAE, which have led to very important judgments on the immunity of heads of government and on foreign act of State. He is regularly instructed, including by the Foreign Office, in cases concerning armed conflict and immunities.

Guglielmo is much in demand as counsel in international arbitration, and he is particularly sought-after by investors and states for his expertise and experience in investment arbitration (under BITs, ECT or investment chapters of FTAs). On the investor side of his practice recent highlights include winning a US$600 million investment claim against a European state. On the state side, they include successfully defending Ukraine from a US$6 billion Energy Charter Treaty claim, and Kenya from a US$2 billion BIT claim. He has acted in arbitral proceedings under all the main institutional rules (ICSID, ICSID- Additional Facility, PCA, UNCITRAL, ICC, SCC, LCIA, Court of Arbitration for Sport). While he works mainly as counsel, Guglielmo has also sat as arbitrator (PCA, ICC, LCIA).

Guglielmo has a very busy advisory practice for governments and multinational corporations. He is regularly instructed to advise on complex legal matters in very sensitive political, economic and diplomatic contexts. In this role, he has worked closely with the upper political and administrative echelons of a number of European, Asian and African states, as well as the top management of multinational corporations.

For many years, Guglielmo combined his professional career at the Bar with academia. He is still Professor of International Law at King’s College London, albeit only on a part-time basis. In past, he was a Fellow of the Lauterpacht Centre for International Law at the University of Cambridge; a Fellow of Merton College, Oxford; and a Visiting Professorial Fellow at Harvard Law School and a Visiting Professor at Columbia Law School. He has published extensively in the field of public international law, and currently sits on the Advisory Board of the American Review of International Arbitration.

Lord Verdirame KC was appointed to a life peerage in October 2022. He will sit in the House of Lords as a non-affiliated member.


Italian (fluent); French (proficient); German (proficient); Modern Hebrew (conversational)

Lawyer Rankings

London Bar > Public international law

(Leading Silks)Ranked: Tier 3

Guglielmo Verdirame KCTwenty Essex ‘He explains matters so clearly, is brilliant with clients and has the brain the size of a planet. He is a persuasive advocate and just a class act.’

London Bar > International arbitration: counsel

(Leading Silks)Ranked: Tier 4

Guglielmo Verdirame KC – Twenty Essex ‘Highly knowledgeable and incredibly persuasive as an advocate.’

Twenty Essex is a ‘leading, go-to set in commercial and investment treaty arbitration‘  with ‘great strength in depth amongst juniors and silks‘. The members have wide-ranging expertise in a range of issues, from traditional strengths in shipping, commodities and insurance, through to multi-jurisdictional fraud disputes and cases with public international law elements. Members regularly work together, and recently Charles Kimmins KC led Mark Tushingham  in a US$134m UNCITRAL arbitration concerning the supply of power turbines to an African state. Guglielmo Verdirame KC is leading Belinda McRae, among others, on behalf of the Republic of Poland in Invenergy v Republic of Poland, a BIT dispute concerning a US$700m investment into the country’s wind energy sector.