Guglielmo acts as counsel in cases before English courts, international courts and tribunals. His cases have involved the full breadth of public international law including investment law, treaty interpretation, immunities and privileges, trade, human rights, law of armed conflict and national security, and boundary disputes.
He has an extensive practice in investment treaty arbitration. Guglielmo regularly acts as counsel, more often in a leading capacity, for both investors and states.
Guglielmo is a member of the UK Attorney General’s A Panel of Counsel in Public International Law. In this capacity, he has been instructed to appear before the International Court of Justice (ICJ), UK Supreme Court and Court of Appeal. Guglielmo was, for example, the public international law specialist in a team of five counsel selected by the UK government for the “Article 50 case” brought by Gina Miller in the aftermath of the Brexit referendum.
He is Professor of International Law at King’s College London (part-time). Guglielmo has published extensively in the areas of public international law, international arbitration, and comparative public law.