Maurice has acted for numerous governments, central banks and other state-owned corporations from all continents, intergovernmental and nongovernmental organisations, multinational and national corporations, and individuals. (A partial list of clients may be provided on request, but for reasons of confidentiality it will not be complete.)  

For most of his career, as well as his practice at the Bar, Maurice developed a distinguished academic reputation. As well as full-time posts at King's College London, Oxford University, and University College London, he has also held visiting professorships in the United States (twice), France (twice) and Australia, as well as giving lectures and seminars by invitation in all continents. He took early retirement from academic life in 2001, and is now Emeritus Professor of International Law at the University of London. He has also published many highly regarded courses of lectures, articles and essays. A detailed account of his academic record and full a list of his publications can be found in the "Achievements" section of his CV.

Types of work include: 

  • Litigation in international courts (e.g. International Court of Justice, European Court of Justice, European Court of Human Rights), international arbitral tribunals (e.g. ICSID) and English courts
  • Transactions (e.g. inter-State negotiations; advising on contracts between States and corporations; restructuring international organisations)
  • Arbitrating
  • Expert evidence in foreign courts and international arbitral tribunals.

Areas covered include:
Territorial sovereignty disputes; land/maritime boundary delimitation; international investment disputes and negotiation of investment protection agreements; sovereign loans; international aviation; state and diplomatic immunity and act of state; constitution and status of international organisations; international aspects of anti-trust law; international employment; compensation/damages for expropriation; state jurisdiction in territorial waters, exclusive economic zone, high seas etc;  jurisdictional disputes, including extraterritorial jurisdiction; pursuit of assets of former heads of state/government; petrochemical extraction; freezing of foreign assets; state succession; international art disputes; international environment (including water resources); international protection of human rights; immigration and asylum; aspects of European Union law concerned with public international law (including legal personality, status of territory, anti-trust, anti-dumping, borrowing powers, & eligibility for membership); self-determination; state responsibility; GATT/WTO; interaction between international law and domestic law.

Maurice has also had a distinguished academic career and is Professor Emeritus of International Law in the University of London. For details, please see the achievements section at the end of his CV.

Maurice is regularly recognised as a leading silk in the latest editions of both the leading legal directories, Chambers UK and Legal 500, for his expertise in public international law and in civil liberties/human rights. Key recent quotes include:

  • "He has very strong advocacy skills, his in-depth understanding and approach to matters is commendable."- Legal 500, 2024
  • "Professor Mendelson is very experienced and knowledgeable, and able to develop new ideas that other people had not thought of, as well as concisely and very clearly articulate opinions on wide-ranging novel legal issues in international law." - Chambers UK, 2024
  • "A world-class legal scholar and barrister."- Legal 500, 2023
  • "He's a brilliant scholar and knows how to write legal opinions in plain terms"- Chambers UK, 2023

Previous quotes include: 

  • "He's insightful, thorough and down to earth."- Chambers UK
  • "He is extremely hard working and a genius"- Legal 500

He is fluent in English (mother tongue) and French; competent in Spanish and Italian; and has some knowledge of German.



Public International Law

Maurice’s practice covers all aspects of public international law, though nowadays about two-thirds of it relates to investor protection. Other major areas include sovereignty disputes, boundary issues (land and sea), the law of the sea more generally, and the international protection of human rights. He advises and represents Governments, international organisations, corporations and (occasionally) individuals.  He also sits as an arbitrator and gives expert evidence to foreign courts and international tribunals. For fuller details, please see the overview of his practice above. 

As previously, Maurice is regularly ranked in the top tier of leading silks for Public International Law in the legal directories.

He has published widely on many aspects of public international law. He has also given expert testimony, by invitation, to the House of Lords Select Committee on the Arctic (July 2014), and has given written evidence to the Chilcot Inquiry into the Iraq War.


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Maurice Mendelson KC is a specialist in international arbitration involving States, State entities and inter-governmental organizations. His practice in this area mainly relates to international investment disputes, where he has sat as an ICSID arbitrator, appeared before and gave expert evidence to investment tribunals, participated in and advised on the negotiation and drafting of investment treaties and contracts, and advised generally. However, he has also worked in the area of commercial arbitration involving States, State entities and intergovernmental organizations, for instance in ICC arbitration and Commercial Court litigation: for example Republic of Serbia v Imagesat International NV [2009] EWHC 2853 (Comm). 

International investment law and arbitration constitute around 70% of Maurice's PIL practice, for which he is praised in Legal 500 2016 as being 'highly intellectual and very pragmatic', and is ranked as a leading silk.

He has published widely in the field, and is Consultant Moderator (formerly Moderator-in-Chief) of OGEMID, the world’s leading electronic bulletin board e-forum on international investment law and arbitration.


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Civil Liberties & Human Rights

Maurice Mendelson KC originally practiced widely in most areas of public law and civil rights, as well as teaching it at Oxford and London Universities.  However, his main speciality is public international law, and currently his involvement in civil liberties and human rights is mainly concerned with their international protection.  He has, inter alia, appeared several times before the European Court of Human Rights. 


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Public & Regulatory

Maurice Mendelson KC originally practiced widely in most areas of public law and civil rights, as well as teaching it at Oxford and London Universities.  However, his main speciality is public international law, and currently his involvement in public law & regulatory is largely concerned with the areas where it overlaps with public international law. But it also involves such matters as assisting in the drafting of domestic constitutional provisions (abroad as well as in the UK), advising on the scope of constitutional authority; questions of self-determination; matters related to accession to the European Union; Brexit; etc. 


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Maurice Mendelson KC has wide expertise in the areas of commercial law that involve public international law.  Some of the work he has done which is listed under the “public international law” or “arbitration” sections has had commercial aspects, whether in the areas of State immunity, international arbitration, or even much of the work he has done in the area of human rights. He is a member of COMBAR, and Consultant Moderator (formerly Moderator-in-Chief) of OGEMID, the world’s leading electronic listserv on international investment law and arbitration.



  • BA, Jurisprudence, University of Oxford, 1964 (first class honours).
  • MA, University of Oxford, 1968.
  • DPhil., University of Oxford,1971.
  • Called to the Bar, Lincoln’s Inn, 1965.

Decorations, prizes, scholarships:

  • Officier de l’Ordre de la Valeur, Republic of Cameroon
  • UK Association for European Law prize 1982
  • Fulbright Visiting Scholar (Harvard Law School), 1977
  • Kennedy Law Scholar, Lincoln’s Inn, 1970-73
  • Leverhulme European Scholar (Institut Universitaire des Hautes Etudes Internationales, Geneva) 1966-7
  • European Law Fund Scholar (Hague Academy of International Law) 1966
  • UN International Law Commission seminar scholarship 1966


Articles, etc.:

  • “Reservations to the Constitutions of International Organisations”, 1971 British Year Book of International Law, 137.
  • “European Magna Carta?”, “New Society”, 26 Aug. 1971.
  • “Diminutive States in the United Nations”, 21 International & Comparative Law Quarterly (1972), 609.
  • “Assessment of Undergraduate Performance”, 21 Jl. of the Society of Public Teachers of Law, 314.
  • “Interim Measures of Protection in Cases of Contested Jurisdiction”, 1972-73 British Year Book of International Law, 259.
  • “Assessment of Law Students' Performance”, in Council of Europe, Proceedings of the 3rd European Conference of Law Faculties, 17 19 April 1974, 85.
  • “The Present Legal Regime of the North Sea: International Law”, in Sibthorp (ed.), The North Sea: Challenge and Opportunity (1975), Chap. IV.
  • (with E. Wilmshurst) “The Present Legal Regime of the North Sea: National Law”, ibid., Chap. V.
  • "International Law" in Annual Survey of Commonwealth Law, 1976, Chap. 13.
  • Annual articles on International Law in The Annual Register, 1978-84.
  • "The Legal Character of General Assembly Resolutions" in Hossain (ed.), Legal Aspects of the New International Economic Order (1980), Chap. 4.
  • "The European Court of Justice and Human Rights", 1 Year Book of European Law (1981), 125.
  • Report for Secretary-General of Council of Europe: "The Impact of European Community Law on the European Convention on Human Rights" (translated into French as "L'incidence du droit Communautaire sur la mise en oeuvre de la Convention Européenne des Droits de l'Homme"), Council of Europe Human Rights File No. 6, 1984 (also published in 3 Year Book of European Law (1983), 99).
  • "The Flux and Reflux of the Law of the Sea", 5 Oxford Journal of Legal Studies (1985) 285.
  • "The Valuation of Nationalized Shares in International Law: Two French Cases", 34 International and Comparative Law Quarterly (1985), 284.
  • "Compensation for Expropriation: the Case-Law" 79 American Journal of International Law (1985) 414 & 1041.
  • "Interim Measures of Protection and the Use of Force by States" in Cassese (ed) The Use of Force in the International Community: Current Developments (1986).
  • "The United Kingdom Nationalization Cases and the European Convention on Human Rights", 57 British Yearbook of International Law (1986), 33-77.
  • "Disentangling Treaty and Customary International Law", 1987 Proceedings of the American Society of International Law, 160.
  • Review Article on Lillich (ed.) The Valuation of Nationalized Property in International Law, Volume IV. 27 Virginia Journal of International Law (1987), 935-943.
  • "Fragmentation of the Law of the Sea", 12 Marine Policy (1988), 192-200.
  • 1st and 2nd Reports of the Rapporteur (with appendices on "Formation of International Law & the Observational Standpoint" and on terminology and concepts used in relation to the formation of customary international law) in International Law Association, 63rd Conference (Warsaw 1988), 1st Interim Report of the International Committee on the Formation of Rules of Customary (General) International Law, 935 & 941.
  • "The Nicaragua Case and Customary International Law", 26 Coexistence (1989), 85-99. Also in Butler (ed.), The Non-Use of Force in International Law (1989), 85. Also translated into Russian as “Delo Nikaragua i obychnoe mezhdunarodnoe pravo” in Danilenko & Ushakov (eds.), Mezhdunarodnoe pravo: sovetskii i angliiskii podkhody (1989).
  • "Practice, Propaganda and Principle in International Law" (Inaugural Lecture), 42 Current Legal Problems (1989), 1.
  • "Are Treaties Merely a Source of Obligation?" in Butler (ed.) Perestroika and International Law (1990), 81.
  • "State Acts and Omissions as Explicit or Implicit Claims" in Le droit international au service de la paix, de la justice et du développement: Mélanges en honneur de Michel Virally (1991), 373.
  • (with S.C. Hulton) "La revendiation par l'Irak de la souveraineté sur le Koweїt", 36 Annuaire français de droit international (1990), 195-227.
  • (with S.C. Hulton) "The Iraq-Kuwait Boundary: Legal Aspects", 1991 Revue Belge de Droit International 293.
  • 3rd Interim Report of the Rapporteur, International Law Association Proceedings of the 63rd Conference (1992), 935, 941.
  • "In Memoriam Georg Schwarzenberger", 63 British Year Book of International Law (1992), xxii-xxvi.
  • "Legal Aspects of the Iraqi Sovereignty and Boundary Dispute with Kuwait" in Schofield & Schofield (eds.), World Boundaries, vol.2: The Middle East & North Africa (1994), 142-57.
  • (with S.C. Hulton) "Iraq's Claim to Sovereignty over Kuwait" in Schofield (ed.), Territorial Foundations of the Gulf States (1994), 117-52.
  • (with S.C. Hulton) "The Iraq-Kuwait Boundary", 64 British Year Book of International Law, (1993) 135-95.
  • (with S.C. Hulton) "Les décisions de la Commission des Nations Unies sur la démarcation de la frontière entre l'Iraq et le Koweit", 1993 Annuaire français de droit international, 178-231.
  • "Principios que rigen los BITs y sus tendencias internacionales" in COINVERTIR (ed.) Politicas de inversion extranjera, (1995), 90.
  • "The International Court of Justice and the Sources of International Law" in Fitzmaurice & Lowe (eds.), 50 Years of the International Court of Justice: Essays in Honour of Sir Robert Jennings (1996), 63-89.
  • "Opinio Juris Sive Necessitatis" in Contemporary International Law Issues: Conflicts and Convergence Proceedings of 3rd Joint American & Netherlands Societies of International Law Conference, 1995 (25-31).
  • "Self-Determination in Kashmir" 1996 Indian Journal of International Law, 1-33.
  • "The Subjective Element in Customary International Law" 66 British Year Book of International Law (1995), 177-208.
  • "The Formation of Customary International Law", 272 Hague Academy of International Law, Collected Courses (1998), 155-410.
  • "International Law in the Past Half Century - and the Next?" 50 Current Legal Problems (1997), 421-41.
  • "The Application of International Legal Concepts of Sovereignty in the Arabian Context", 3 Geopolitics (1998) 133-38.
  • "The Practitioner in Domestic Law" in Wickremasinghe (ed.), The International Lawyer as Practitioner (2000), 165-84.
  • International Law Association, International Committee on the Formation of Customary (General) International Law, Final Report of the Committee, including London Statement of Principles relating to the Formation of General Customary International Law, in International Law Association, Report of 69th Conference (2000), 712-777: also on internet at
  • "The Curious Case of Qatar v Bahrain in the International Court of Justice", 72 British Year Book of International Law (2001), 183-211.
  • "On the Quasi-Normative Effect of Maritime Boundary Agreements" in Liber Amicorum for Judge Shigeru Oda (2002), 1069-86.
  • “State Responsibility for Breach of Interim Protection Orders of the International Court of Justice” in Fitzmaurice & Sarooshi (eds.), State Responsibility & the International Court of Justice (2004), 35-53. 
  • “The Effect of Customary International Law on Domestic Law: An Overview”, 4 Non-State Actors and International Law (2004), 75-85.
  • “The Definition of ‘International Organization’ in the International Law Commission's Current Project on the Responsibility of International Organizations” in Ragazzi (ed.), Essays in Memoriam Oscar Schachter (2005), 371-89.
  • “The Cameroon-Nigeria case in the International Court of Justice:  Some Territorial Sovereignty and Boundary Delimitation Issues”, 75 British Year Book of International Law (2004), 223-47.
  • "Does the Loewen Award Endanger the Credibility of the NAFTA Dispute Settlement Mechanism?"  6 Journal of World Investment & Trade (2005), 84-87.
  • "The Runaway Train: The 'Continuous Nationality Rule' from the Panevezys-Saldustiskis Railway Case to Loewen", in Weiler (ed.), International Investment Law and Arbitration: Leading Cases from the NAFTA, ICSID, Bilateral Treaties and Customary International Law (2005), 97-149. 
  • "Recognition of Referendum Results" in Elezovic (ed.), Legal Aspects for [sic] Referendum in Montenegro in the Context of International Law and Practice (2005), 103=111.
  • The Requirement of Continuous Nationality” in Ortino & others,  Investment Treaty Law : Current Issues, vol. 2 (2007), 41-53.
  • Comment on [Schwebel] “May preparatory Work be Used to correct Rather than confirm the ‘clear’ meaning of a Treaty Provision?”, 2 Transnational Dispute Management (Nov. 2005), 
  • "What laws are companies currently bound to? What changes have been proposed and what are the likely developments?”, 2 Oil, Gas and Energy Law Intelligence (OGEL) Journal (2005),
  • "United Nations Conferences on the Law of the Sea: UNCLOS I (1958) and II (1960)", in Oxford Encyclopedia of Maritime History (2007), vol. 4, 237-46. 
  • “Case Concerning Maritime Delimitation and Territorial Questions between Qatar and Bahrain (Qatar v Bahrain)” in Max Planck Encyclopaedia of International Law (2nd ed.,
  • "Right of Passage over Indian Territory Case" in Max Planck Encyclopaedia of International Law (2nd ed.,
  • “Customary International Law” in Cane & Conaghan (eds.), The New Oxford Companion to Law (2008), 291-93.
  • “International Dispute Settlement:  Developments and Challenges”, 61 Revue hellénique de droit international (2008), 463-75.    
  • "In Memoriam Sir Francis Vallat, GBE, KCMG, QC (1912-2008)", 79 British Year Book of International Law (2008), 3-6.
  • “Double Counting and the Origin of Lucrum Cessans: Introductory Comments” 41-45, in Bjorklund, Laird & Ripinsky (eds), 3 Investment Treaty Law: Current Issues (2009), 41-45.
  • "Investment and BITs in Clinical Isolation?  Conflicting Legal Obligations of Host States", 24/2 ICSID Review (2009), 82-87.
  • "Issues Relating to the Identity of the Investor" in 5th Annual Fordham Law School Conference on International Arbitration and Mediation 2010 22-32.
  • Panel discussion: ' Arbitration as a growth industry: where will the growth come from - the BRICs and other emerging economies? Is it a case for supply-side economics? 15th Geneva Global Arbitration Forum (2010). To read this paper click here:
  • "Issues relating to the Identity of The Investor", in Rovine (ed.), Contemporary Issues in International Arbitration and Mediation: the Fordham Papers, vol. 4 (2010), 22-32.
  • ''Sir Francis Vallat, GBE, KCMG, QC', in Dictionary of National Biography.  
  • (With M. Paparinskis) ‘Bail-Ins and the International Investment Law of Expropriation: in and Beyond Cyprus’, Butterworths Journal of International Banking and Financial Law (Sept. 2013), 475-79.
  • ‘The Importance of Instructions’, in Ehle & Baizeau,  Essays in Honour of Michael E. Schneider - Stories from the Hearing Room. Experience from Arbitral Practice (2015), 115-21. 
  • (With M. Paparinskis) ‘Bail-ins and International Investment Law: in and beyond Cyprus’ in Hofmann, Schill, & Tams (eds), International Investment Law and the Global Financial Architecture (Edward Elgar 2017), 193-210.
  • Comment on C. Parry, "The Sources and Evidences of International Law (1965)" in Anthology of British Contributions to International Law, volume I, chapter 22 (in the press).
  • Comment on R. Jennings, "Reflections on the Subsidiary Means for the Determination of Rules of Law (2003)", ibid, chapter 23.
  • "Inter-State Arbitration: Current Issues and Contemporary Challenges" in Lim (ed.), The Cambridge Companion to International Arbitration (in the press)

Reviews (inter alia):

  • American Journal of International Law
  • British Year Book of International Law
  • European Law Review
  • International & Comparative Law Quarterly
  • ICSID Review
  • International Affairs
  • Law Quarterly Review
  • Lloyd's Maritime & Commercial Law Quarterly
  • Modern Law Review
  • Marine Pollution Bulletin
  • Times Higher Education Supplement


  • For TV and radio, in UK and abroad, on various aspects of International Law;
  • UN Audiovisual Library of International Law, lecture on customary international law;
  • British Institute of International & Comparative Law, online lecture on International Investment Law & Dispute Resolution.

Doctoral Thesis:

Acquisition of Membership in Selected International Organizations (Oxford University, 1971).


  • Master of the Bench of Lincoln's Inn
  • Member, Editorial Advisory Board, British Year Book of International Law.
  • Member, Editorial Board, Current Legal Problems 1991-94.
  • Chairman (formerly Rapporteur), International Law Association International Committee on Formation of Customary (General) International Law, 1985-2000.
  • Chairman, International Law Association Study Group on The Use of Domestic Law Principles for the Development of International Law (2012-date). 
  • Member, International Law Association, International Committee on Aspects of State Succession, 1998-2008.
  • Member, International Law Association, International Committee on the Exclusive Economic Zone, 1983-92.

Membership of professional bodies, learned societies etc:

  • International Law Association (Council, British Branch) 
  • American Law Institute
  • Société française de droit international
  • London Court of International Arbitration
  • British Institute of International and Comparative Law (International Law Advisory Panel)
  • Fellow of the Royal Geographical Society
  • Royal Institute of International Affairs
  • American Society of International Law
  • International Bar Association
  • Investment Treaty Forum
  • Commercial Bar Association
  • European Circuit

Past academic posts:

  • Chair of International Law, University College, London University 1987 - September 2001 (now Emeritus).
  • University Lecturer in Law (C.U.F.), Oxford University 1975 - 1986.
  • Official Fellow and Tutor in Law, St. John's College, Oxford, 1975 - 1986 (Senior Dean 1985).
  • Lecturer in Laws, King's College, London University, 1968 - 74.

Visiting posts:

  • Visiting Professor of International Law, University of Paris X (Nanterre), 2002-3.
  • Freehills, Hollingdale & Page Fellow and Visiting Professor of International Law, University of New South Wales, 1999.
  • Visiting Professor of International Law, Institut des Hautes Etudes Internationales, Paris, 1993.
  • Visiting Professor of International Law, University of Paris II (Panthéon - Assas), 1993.
  • Visiting Professor of International Law, University of Pennsylvania, 1986.
  • Visiting Professor, University of North Carolina, Chapel Hill, Law School, 1982.
  • Visiting Scholar, Harvard Law School, 1977.

Universities & Institutions at which Guest Lectures, guest papers etc. given, include:

  • Academy of International Law, The Hague
  • American Society of International Law
  • University of California, Berkeley, Law School
  • University of Catania
  • Charles University, Prague
  • Coinvertír, Colombia (members of Congress, etc.)
  • Council of Europe
  • Czech Society of International Law
  • European University Institute
  • University of Florence
  • Harvard Law School
  • Institute of State & Law, Soviet Academy of Sciences
  • International Chamber of Commerce, Institute of International Business Law & Practice
  • Judge Advocate General School, Charlottesville, Virginia
  • Los Andes University, Bogotà, Colombia
  • New York Law School
  • New York University Law School
  • University of N. Carolina, Chapel Hill, Law School
  • University of Paris I (Panthéon - Sorbonne)
  • University of Pisa
  • University of Siena
  • Stanford University Law School
  • University of Texas Law School
  • University of Virginia Law School
  • Yale Law School

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