Steptoe & Johnson has hired outgoing London International Disputes Week co-chair Professor Loukas Mistelis from Clyde & Co as an arbitration partner in London.
Mistelis, well known for his academic profile at Queen Mary University of London, will continue to practise exclusively in international commercial and investment arbitration. His work includes advising and representing clients, as well as acting as an expert and arbitrator, in complex cross-border disputes. He leaves Clyde & Co after four years.
He has handled matters before institutions including the ICC, ICSID, LCIA, PCA, UNCITRAL, SCC and DIAC. His practice covers disputes involving states, state-owned entities and multinational companies across Europe, the Americas, the Middle East, Africa and Asia.
The appointment gives Steptoe additional capability in sectors including energy, infrastructure, finance, aviation, construction, defence, mining and natural resources. The firm said Mistelis’s experience across both investor-state and commercial arbitration would strengthen its offering on high-value international matters.
“Loukas is one of the most respected figures in international arbitration globally,” said Amy Lentz, Steptoe’s international disputes practice leader. “His ability to combine top-tier academic insight with extensive practical experience across both commercial and investor-state disputes significantly enhances our offering to clients facing their most complex, high-stakes matters.”
Alongside his legal practice, Mistelis is the Clive Schmitthoff Professor of Transnational Commercial Law and Arbitration at QMU’s Centre for Commercial Law Studies. Mistelis, who has served as director of the university’s School of International Arbitration, will continue teaching following the move, having led successive research studies there.
Mistelis said: “The firm’s strong global platform, combined with its excellence across both commercial and investor-state arbitration, makes it an ideal fit for my practice and my clients. I am particularly pleased that all my key clients are following me to Steptoe.”
Commenting on LinkedIn, Mistelis added: “Steptoe is a disputes powerhouse with some wonderful colleagues in the various offices, providing an excellent foundation for my practice to grow,” while teaching at Queen Mary.
Mistelis also serves on the board of trustees of the Cairo Regional Centre for International Commercial Arbitration, is a member of the Saudi Centre for Commercial Arbitration Court and has sat as arbitrator across all the major arbitral institutions, having co-chaired the popular Arbitral Institutions Congress within LIDW in successive years.
Along with Jonathan Cary, he is one of the retiring co-chairs of LIDW, following the expiry of his two-year term of office. Mistelis and Cary will be replaced by Mayer Brown’s Luiz Abiom, a fellow arbitration partner, and Stewarts’ litigation partner Sophie Lalor-Harbord as co-chairs alongside Pinsent Masons’ Emilie Jones.
Mistelis’s departure from Clyde & Co is the latest in a series of exits involving specialist international arbitration partners at the firm. Energy arbitration partner Richard Power recently moved to Fieldfisher, while a two-partner team led by Ben Knowles joined Keystone Law.
Knowles told GLP: “Loukas is a super lawyer, valued mentor and one of the most knowledgeable arbitration experts that I know. I have no doubt that his busy practice will go from strength to strength.”
David Leckie, a partner at Clyde & Co, confirmed Mistelis’s departure, saying: “We thank him for his contribution and wish him well for the future.”
Leckie said Clyde & Co retained “a leading international arbitration practice, with over 200 partners and 400 lawyers acting on arbitration matters globally”.
He added that the practice had been “further strengthened with the addition of 17 partners globally, through a combination of promotions and lateral hires, who represent clients in arbitrations across a number of key jurisdictions” since May 2025.
“As is typical within a large international practice, there are changes in team compositions over time,” Leckie said, reiterating the firm’s work continued across the main arbitral centres and on a range of complex disputes.
He said Clyde & Co’s arbitration capability was “fully integrated within our sector-aligned disputes structure, reflecting a continued focus on aligning arbitration expertise with our core industry groups. This enables us to support clients through teams combining specialist disputes capability with deep sector expertise”.
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