He is Professor of Law and Director of the Centre on International Courts and Tribunals in the Faculty, and a key member of staff in the Centre for Law and the Environment. His teaching areas include public international law, the settlement of international disputes (including arbitration), and environmental and natural resources law. As a practicing barrister he has extensive experience litigating cases before the International Court of Justice, the International Tribunal for the Law of the Sea, the International Center for the Settlement of Investment Disputes, and the European Court of Justice. He frequently advises governments, international organisations, NGOs and the private sector on aspects of international law. In 2003 he was appointed a Queen's Counsel. He has been appointed to lists of arbitrators maintained by ICSID and the PCA.