Calum Mulderrig

Practice Overview

Calum is a leading junior barrister, with a broad practice that covers all core areas of commercial work, including civil fraud, banking and financial services, insolvency, crypto and securities litigation. He is ranked as a rising star in banking litigation and cryptocurrency disputes, and as a leading junior in public international law.

As a former solicitor at leading international law firm Quinn Emanuel Urquhart & Sullivan, Calum enjoys working in teams on large disputes, but he is equally comfortable acting as sole counsel and has appeared unled in the High Court, before the DIFC courts, and before international arbitration tribunals.

He is described in the directories as “very hard working and technically reliable”, “a fantastic junior who is exceptionally hardworking in a way that stands out from his peers”, a barrister who is “very adept at getting across the law”, has a “clear legal mind” and “reads widely and drafts in a natural and convincing way”.

Calum’s recent instructions include acting for the claimants in three of the most high profile securities litigation claims under s.90A of FSMA 2000, against G4S, Serco and Barclays (two of which were included as “Top 20” cases for 2024 in the Lawyer). Those proceedings resulted in several significant judgments in the securities litigation field, including as to the definition of “PDMR” under FMSA (Allianz v G4S Ltd [2022] EWHC 1081 (Ch)) and the circumstances in which parties are entitled to review privileged information of the company in which they are shareholders (Various Claimants v G4S PLC [2023] EWHC 2863 (Ch)). He acted unled before the DIFC Court of First Instance, obtaining immediate judgment under a guarantee in the amount of c. USD 500 million on behalf of a syndicate of lenders against guarantors, and subsequently resisted an application for permission to appeal that judgment to the DIFC Court of Appeal. He appeared with Raj Pillai KC before the DIFC Court of Appeal in what is now the leading authority on fraudulent misrepresentation in the jurisdiction (SBM Bank (Mauritius) Ltd v (1) Renish Petrochem FZE (2) Mr Hiteshkumar Chinubhai Mehta [2024] DIFC CA 011) and successfully acted with Jonathan Nash KC for a large offshore trust defending breach of contract claims in relation to pension entitlements, succeeding in a counterclaim and obtaining an indemnity costs order (Davies v Novatrust Ltd [2023] EWHC 1196 (Ch)).

Calum’s matters are frequently international in nature and he has appeared before numerous international arbitration tribunals in disputes conducted under the rules of major institutions, including the LCIA, ICC, ICSID and AAA. He successfully acted in international arbitration proceedings with Christopher Harris KC and Tamara Kagan, obtaining a USD 100 million award for a claimant under a political risk insurance policy. He has also significant experience acting in disputes on behalf of or against sovereign states and, together with Christopher Harris KC and Mark Wassouf, recently succeeded in an action against Bosnia in ICSID proceedings related to a failed hydropower project, subsequently resisting in full the state’s application for annulment (Viaduct d.o.o. Portorož, Vladimir Zevnik and Boris Goljevšček v. Bosnia and Herzegovina (ICSID Case No. ARB/16/36)). Calum is fluent in Spanish and is able to take instructions which have a Spanish language element. He also has good French and basic Italian.

Calum maintains an academic interest in the law and has contributed to several leading practitioners’ texts across different fields, including Paget’s Law of Banking (Sixteenth Edition, 2023), the Investment Treaty Arbitration Review (Eighth Edition, 2023) and an upcoming practitioners text on Securities Litigation (2025).