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Iain Maxwell

Of Counsel

Iain specialises in international arbitration and public international law.



Iain is an experienced dispute resolution lawyer and advocate, who specialises in arbitration (in particular treaty arbitration) and public international law. He regularly represents investors and states in claims under investment treaties, and advises both corporations and states on a broad range of public international law issues, including sovereign immunity, sanctions, and boundary issues.

Iain has worked out of our London and Singapore offices on cases arising from all major industry sectors and in arbitration proceedings administered by all the major arbitration institutions including the International Centre for Settlement of Investment Disputes (ICSID), the International Chamber of Commerce (ICC), the London Court of International Arbitration (LCIA), and the Singapore International Arbitration Centre (SIAC).

Iain frequently lectures and speaks at conferences on international arbitration.

Iain's experience includes acting for:

  • Nord Stream 2 AG in an ongoing claim against the European Union under the Energy Charter Treaty. This claim, which relates to the impact of new European Union legislation on a major gas pipeline, is the first investment arbitration brought against the European Union
  • Vedanta Resources in an ongoing UNCITRAL arbitration claim against India under the UK-India BIT. The claim concerns changes to Indian tax legislation resulting in a tax charge of over US$3 billion on our client's subsidiary
  • Standard Chartered Bank and a subsidiary in three related ICSID arbitrations relating to a power station in Tanzania (ICSID Case No. Arb 10/12; ICSID Case No. Arb/10/20; and ICSID Case No. ARB/15/41), including a claim against the United Republic of Tanzania under the United Kingdom–Tanzania BIT. As a result of these arbitrations, the client obtained a favourable US$148 million Award in September 2016 and successfully defended attempts to overturn the award, and subsequently obtained a further favourable Award of US$185 million in September 2019.
  • United Utilities (Tallinn) B.V. and an Estonian subsidiary in an investment treaty arbitration against the Republic of Estonia brought under the Netherlands-Estonia BIT (ICSID Case No. ARB/14/24).
  • Aguas del Tunari in an ICSID arbitration against Bolivia for alleged breaches of the Netherlands-Bolivia BIT. The claim involved allegations of expropriation of a water concession. A successful decision was obtained at the jurisdiction stage and settlement agreed thereafter (ICSID Case No. ARB/02/3)
  • BP and Rio Tinto on a US$500 million ICSID arbitration brought against them by the Government of the Province of East Kalimantan, Indonesia, arising out of a coal mining project in Indonesia. BP and Rio Tinto were successful in resisting jurisdiction (ICSID Case No. Arb 07/3)
  • The Government of Malaysia in a successful billion-dollar arbitration against the Republic of Singapore concerning the interpretation of a 1990 treaty



  • Iain is ranked as an up and coming lawyer for both Public International Law and International Arbitration in Chambers UK (2021).  In relation to Public International Law Chambers notes that:

Iain Maxwell has a growing reputation for his PIL and international arbitration practice. He is particularly adept at handling BIT claims and ICSID arbitrations, with further expertise in international sanctions. ‘He is the person I would call on for investment treaty arbitration - he is extremely up to date on trends in the market.’"

In relation to International Arbitration Chambers notes that:

Iain Maxwell has a thriving arbitration practice and fields significant expertise in investment treaty disputes. He represents clients across a range of industries and demonstrates notable strength when handling complex BIT claims. ‘Iain Maxwell is a fantastic lawyer. He's extremely cerebral and gets the numbers as well as the legal side of the case.’"

  • Similarly, Chambers (2020) noted that:

"Iain Maxwell is of counsel and has a growing reputation for his practice in PIL. He has acted in numerous ICSID investment arbitration cases and can also advise on other areas including the Law of the Sea and international sanctions. Sources say: "His knowledge of the subject is very impressive indeed," and also note: "He is capable of dealing a knockout blow from nowhere during cross-examination."

  •  Legal 500 UK (2021) ranks Iain as a “rising star” in Public International Law, and lists Iain as an experienced Of Counsel and key lawyer within Herbert Smith Freehills tier-1 ranked International Arbitration practice, with the testimonial that ‘Iain Maxwell is phenomenally intelligent with a great grasp of not only the legal side of a case but the damages aspect.’
  • Iain was also ranked in the area of Public International Law in Legal 500 UK (2020), which noted that:

"Iain Maxwell is not afraid to grapple with detail and then ultimately cut through the noise to give you meaningful advice that can be used to make a decision."

Iain is also recognised by Who's Who Legal in their 2018 Future Leaders – Arbitration list, for practitioners aged 45 or under who are considered to be the future leaders of the international legal community


Iain has a First Class law degree from Jesus College, Cambridge University, having been awarded scholarships by both Jesus College and Cambridge University. 

Iain specialises in international arbitration and public international law.

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