Mark is the Global Co-Head of International Arbitration team and the International Head of Energy Disputes
Mark has 20 years' experience of representing private multinational clients and states and state-owned entities in complex and high-value international disputes in both arbitration and litigation.
He regularly acts as lead counsel and advocate in multi-million and billion dollar arbitration matters before international tribunals, including in state-to-state cases. These include some of the largest cases of the last decade. He has deep experience of energy, engineering and industrial sector disputes, in matters involving different governing laws and regulations, and on projects spanning Europe, the Middle East and Asia. He is adept at managing large teams in cross-border cases, with witnesses, experts and counsel in a wide range of disciplines. He also frequently advises on energy pricing disputes under long-term contracts, including LNG.
Mark has led cases under most major arbitral institutional rules as well as ancillary multi-jurisdictional court proceedings such as injunctions, challenges to awards and enforcement matters. In addition, he acts in major court litigation at all levels and in different divisions in the English High Court. His litigation experience encompasses large M&A disputes, IP (including pharma and tech), group action and environmental claims, public law challenges and tax-related disputes.
His cases also often include alternative dispute resolution mechanisms (such as mediation or expert determination) and he has led high-profile regulatory investigation matters for energy sector clients.
Before joining Eversheds Sutherland, Mark worked in the international arbitration group at Freshfields, London. He holds a Law MA from Downing College, Cambridge University.
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Representative experience includes:
- representing a consortium of international energy companies in UNCITRAL arbitral proceedings concerning defective workmanship at a facility in Central Asia
- acting for a minority shareholder in a high-value joint venture dispute concerning pan-European renewables projects
- representing a global energy company in multi-million dollar ICC arbitration proceedings concerning a major Middle Eastern solar project
- acting for a state-controlled European energy company in a dispute with its co-venturer regarding the management and operation of several major renewable energy projects in the UK
- representing one of the world’s largest national oil companies in multi-billion-dollar gas supply ad hoc arbitrations
- acting for a state-owned enterprise in a multi-billion dollar LNG price redetermination
- advising a consortium of energy majors in a multi-billion dollar gas pricing dispute with the state-affiliated project participants
- acting for a renewable energy developer in a dispute concerning rights associated with a major onshore wind farm
- acting for a multinational industrial company in ICC arbitration proceedings defending equipment claims valued at several hundred million Euros
- acting for a global energy services contractor in relation to LCIA disputes arising from a major offshore project
- acting for a global energy client in ICC arbitration claims arising from the defective supply of wind turbines on a large European project
- representing an international power company regarding parallel litigation and arbitration claims concerning investments in power projects in Libya
- representing an IT company in high-value ICC claims relating to data projects
- acting for a global travel services provider in defending billion-dollar claims in the English High Court for breach of confidence and copyright infringement
- representing, as counsel and advocate, The Islamic Republic of Iran in a multi-billion dollar state-to-state arbitration before the Iran-US Claims Tribunal in The Hague
- representing a global food products company in English High Court claims for multi-million-pound damages connected to a gas processing system
- acting for one of the world’s largest investment management companies regarding claims arising from regulatory accreditation of renewables assets
- acting for an investment bank in multi-billion dollar international BIT arbitration proceedings
- advising an oil super-major in defending multi-jurisdiction group action proceedings arising from oil spills in North Africa
- defending IP infringement proceedings for a US medical devices and healthcare company in relation to a blockbuster drug
- representing the world’s largest independent power producer in high-value warranty claim proceedings concerning Europe’s biggest gas-fired power station
- acting for a major European energy company in a price revision dispute with a gas supplier under a long-term contract
- acting for a global real estate company regarding claims connected to the COVID-19 pandemic
- acting for a state client successfully defending $500m US judgment enforcement proceedings in the English High Court
- acting for a global renewables sector investor in fraud claims connected to solar projects benefiting from renewables incentives schemes
- acting for an oil and gas company in challenging a high-value arbitration award before the English High Court
- acting for energy clients, including Big 6 and mid-tier clients, in Ofgem regulatory investigations and related claims, including judicial reviews
Client testimonials and accolades:
- “Mark's ability to keep a cool head in difficult situations is impressive. He keeps the show on the road.” (2026, Litigation, Chambers Guide to the Legal Profession)
- “Mark delivers high-quality expertise on complex matters.” (2026, Litigation, Chambers Guide to the Legal Profession)
- “Mark heads the team well and has wide-ranging knowledge of different legal systems and laws. He is ideally placed to coordinate complex matters and is intellectually strong, practical and strategic.” (2026, Litigation, Chambers Guide to the Legal Profession)
- “Mark is an outstanding lawyer. He has deep technical expertise, excellent judgement and is a pleasure to work with. He delivers high quality expertise on complex matters.” (2026, Public International Law, Chambers Guide to the Legal Profession)
- “Mark Howarth brings strong multidisciplinary insight to complex matters and combines this with sound judgment and a highly pragmatic approach. He is also exceptionally pleasant to work with, which makes a real difference in long-running and demanding cases.” (2026, International Arbitration, Chambers Guide to the Legal Profession)
- “Mark is a real energy industry specialist.” (2026, International Arbitration, Chambers Guide to the Legal Profession)
- “Mark Howarth does an excellent job with client management and handles cultural sensitivities really well. He is very strong intellectually too, as well as practical and strategic.” (2026, International Arbitration, Chambers Guide to the Legal Profession)
- "He has a blue-chip City background. He brings skill and ability to lead the arbitration and energy groups. He has been dealing with a huge case of massive significance, and Mark is a master at keeping a team cohesive and calm. He gets the most out of every team member. He is an excellent team leader and is charming to work with.” (2025, International Arbitration)
- “I worked with Mark Howarth, who is a giant of the space, making a stronger practice with a wide team of talented lawyers.” (2025, International Arbitration)
- “Mark is an absolute operator in all the best senses. The value of the work he’s dealing with is extremely impressive. He is bright and very astute.” (2025, International Arbitration)
- “Mark Howarth's client service and general level of service, level of sophistication and commercial vision are all strong. He is a dedicated and detail-oriented lawyer who is strong in managing teams in complex cases.” (2025, International Arbitration, UK)
- "Mark is my no.1 choice when I need support on a dispute which is about to turn formal. I know that he understands our needs, his work always meets our short and long term objectives, he is easy to communicate with and delivers." (General Counsel, global energy client)
- "Mark is working on large and complex arbitration matters arising out of international treaties and commercial agreements covering a large area of diverse issues. His capability in case presentation and cross-examination has been very professional and effective. He is a trustworthy and educated lawyer and the clients have confidence in him." (Counsel, global energy client)
- "I have been working with Mark for several years. He has an excellent ability to provide crystal clear advice and see the issues from an angle that does not get the attention of most advocates. He always thinks a few steps ahead and understands legal and commercial issues. He would be irreplaceable for any team, is a fluent advocate and cross-examiner. Last but not least, it is a pleasure to work with him." (Senior Counsel, energy arbitration client)
- "I have now worked with Mark for several years. I found it very easy to rapidly build up a rapport with him based on respect for his knowledge and insight, but also his ability to generate confidence amongst my key internal stakeholders at Board level - his assured performances with our CEO was always helpful for me." (General Counsel, energy regulatory client)
- "Mark was the relationship partner for my five years at the company. I still regularly refer to him as a great example of how the partner role should be done: he was an ideal mix of brilliantly responsive, helpfully intrusive and proactive, excellent with feedback - which all left me feeling positive about the relationship: we were equal partners and each respected the other's objectives and point of view. He has also always been great fun to work with." (Regional General Counsel, global client)
- International Arbitration - A Practical Guide – Globe Law & Business – December 2012 (contributor)
- National Navigation Co v Endesa Generacion SA (The Wadi Sudr): Dead Ahead? West Tankers sails on in the Court of Appeal in The Wadi Sudr – 2010
- After West Tankers – Rise of the “Foreign Torpedo”? – Arbitration: The International Journal of Arbitration, Mediation and Dispute Management – 2009
- Chambers UK, 2025: “A true leader as an energy industry specialist. He works for the highest standards.”
- Legal 500 2025: “Mark Howarth is a real star. He is calm, considered and hugely experienced. He is also a pleasure to work with.”
- Legal 500: “I would single out Mark Howarth as the standout. He is the full package: strategic, clever, easy to work with and pragmatic”
- Legal 500: “Mark Howarth is really a standout figure. He’s unflappable and charming, and very clever.”
- Legal 500: “Mark Howarth – admirable grasp of the detail and availability.”
- Thomson Reuters: “Stand-out Lawyer” identified by senior in-house counsel through the Thomson Reuters Sharplegal survey
- Senior Courts of England & Wales, Solicitor
- Masters degree in Law from Downing College, University of Cambridge