Dr Hailes is a general international lawyer with special interests in energy, investment, environment, and arbitration: inter-State, investor-State, and commercial. He joined the LSE Law School as an Assistant Professor in January 2023. He has been Assistant General Editor of the ICSID Reports since 2018.

Dr Hailes was admitted as a barrister and solicitor of the High Court of New Zealand in 2017. He holds a BA in Politics and an LLB with Honours from the University of Otago, where he returned as visiting lecturer, and an LLM in International Law (First Class) and a PhD in Law from Trinity College, University of Cambridge. His thesis examined the application of customary international law in investment treaty arbitration, focusing on the economic rights of States: expropriation, taxation, and regulation. Several of his publications have further explored the doctrinal and historical connections between investment treaty disputes and general international law, addressing public health, natural resources, attribution of conduct, and valuation of compensation.

Before arriving at the LSE, Dr Hailes clerked for an appellate judge, practised commercial litigation, volunteered for climate and trade NGOs, and held several research, teaching, and editorial roles. He was co-Editor-in-Chief of the Cambridge International Law Journal and a Research Associate with the PluriCourts Centre of Excellence at the University of Oslo. As a doctoral student, he taught graduate workshops in international investment law and coached Cambridge’s team for the Philip C Jessup International Law Moot Court Competition. He now administers the Jessup at the LSE Law School and co-chairs a Masterclass on the Practice of International Arbitration, run by Three Crowns LLP.   

Alongside his academic duties, Dr Hailes has worked on matters before international tribunals, including the International Court of Justice. He is a member of the Academic Forum on ISDS, the Trade and Public Policy (TaPP) Network, the American Society of International Law, and the European Society of International Law.