Sebastian Mellab

Professional practice

Sebastian has a broad commercial and arbitration practice, with experience spanning civil fraud, commodities, shipping, energy, banking and joint venture disputes. He has conducted oral advocacy in the Commercial Court and the Chancery Division. He has also acted in disputes under, or otherwise involving, the LCIA, LMAA, ICC, DIAC, SIAC, UNCITRAL, and Swiss Rules.

Sebastian’s recent and current instructions include:

acting (led by Mark Howard KC and instructed by Mishcon de Reya) for Nigeria in Nigeria v P&ID, a successful eight-week fraud challenge to arbitration awards worth US$11bn+ arising out of a gas processing contract. The case won GAR’s 2024 Most Important Decision Award;
acting for an S&P 500 company in a US$100m+ LCIA arbitration (2026) concerning the supply of a soft commodity;
acting for a trading company in a US$10m+ set of parallel SIAC and DIAC arbitrations (2025) arising out of a multi-cargo sale of gasoline;
acting (led by Tim Akkouh KC and instructed by Slaughter and May) in Chugga Chugg v Privinvest [2025] EWHC 585 (Comm), a two-week shipbuilding trial arising out of underlying LMAA awards, appearing (unled) before Bright J in a post-judgment asset disclosure application (2026);
acting (led by Claire Blanchard KC and instructed by HFW) in Moeve Trading SAU v Mael Trading FZ LLC [2026] EWHC 17 (Comm), a US$13m+ action for the price of gasoline and gasoil sold FOB;
acting (led by Claire Blanchard KC and instructed by HFW) in Owners of the M/T Harbour Progress v Mael Shipmanagement, intervening in Commercial Court proceedings by shipowners under letters of indemnity issued to procure discharge of cargo;
acting (led by Stephen Houseman KC and instructed by Clyde & Co) in Arbitral v Britannia Financial Group (2025) (reported in The Lawyer and the FT), a Commercial Court earn-out trial (which settled on the first day) concerning the sale of a financial brokerage and Tether’s US$1bn deposit of securities, appearing (unled) before Knowles J in an interlocutory application (2025);
acting (led by Tim Akkouh KC and instructed by Candey) in Rogachev v Goryainov [2024] EWHC 3317 (Ch); [2024] EWHC 2436 (Ch), a US$40m+ 12-day Chancery trial and 3-day consequential hearing concerning the breakdown of a joint venture, involving forensic accountancy and allegations of dishonesty, obtaining indemnity costs;
acting (led by Angeline Welsh KC and Clifford Chance) in BCB and Prize Holdings v Belize (No. 2023-38), a PCA arbitration arising out of a project for the development of a cruise ship terminal and bulk-handling and cargo facilities.

Sebastian speaks fluent Dutch and French. He studied law at Cambridge (where he came fourth in his year and top of his year in Commercial Law and Conflict of Laws), Oxford and Harvard.

Arbitration & related court applications

Sebastian has experience of international and commercial arbitrations (under various arbitration rules) and related court applications, including challenges to awards under sections 67 and 68 of the Arbitration Act 1996:

acting (led by Mark Howard KC and instructed by Mishcon de Reya) for Nigeria in Nigeria v P&ID, an eight-week fraud challenge to $11bn+ arbitration awards under section 68. The case won Global Arbitration Review’s 2024 Most Important Decision Award and is said to have sent “shock waves” through “the usually discreet world of international arbitration” (The Times);
acting for an S&P 500 company in a US$100m+ LCIA arbitration (2026);
acting in a US$10m+ set of parallel SIAC and DIAC arbitrations (2025);
acting (led by Tim Akkouh KC and instructed by Slaughter and May) in Chugga Chugg v Privinvest [2025] EWHC 585 (Comm), a two-week trial arising from underlying LMAA awards, considering the impact of German insolvency proceedings on the status and effect of those awards under a shipbuilding refund guarantee;
acting (led by Angeline Welsh KC and Clifford Chance) in BCB and Prize Holdings v Belize (No. 2023-38), a PCA arbitration under the UNCITRAL rules arising out of a port infrastructure project;
acting in a US$10m+ Swiss-seated arbitration (2023);
assisting a Member of Chambers in a US$10m+ ICC arbitration (2022).

Banking & financial services

Sebastian has experience of a number of banking and financial services disputes:

acting (led by Stephen Houseman KC and instructed by Clyde & Co) in Arbitral v Britannia Financial Group (2025) (reported in The Lawyer and the FT), a Commercial Court earn-out trial (which settled on the first day) concerning the sale of a financial brokerage and Tether’s US$1bn deposit of securities, appearing (unled) before Knowles J in an interlocutory application;
acting (led by Tim Akkouh KC and instructed by Slaughter and May) in Chugga Chugg v Privinvest [2025] EWHC 585 (Comm), a two-week trial raising complex issues of guarantee interpretation, including whether the instrument operated as a demand guarantee or a surety guarantee;
acting in Commercial Court proceedings concerning claims by banks against guarantors under finance guarantees;
assisting a Member of Chambers with advice on claims arising out of financial market manipulation;
assisting a Member of Chambers with advice on the merits of potential claims in negligence and misrepresentation against a bank arising out an alleged advisory duty;
assisting a Member of Chambers in Bidzina Ivanishvili v Credit Suisse, an appeal against a Bermuda judgment involving claims in negligence and misrepresentation against a bank.

Civil Fraud & Asset Tracing

Sebastian has experience of a number of civil fraud disputes:

acting (led by Mark Howard KC and instructed by Mishcon de Reya) for Nigeria in Nigeria v P&ID, an eight-week Commercial Court fraud trial leading to the setting aside of arbitration awards worth US$11bn+, involving bribery, perjured evidence and the improper obtaining and use of privileged documents;
acting (led by Tim Akkouh KC and instructed by Candey) in Rogachev v Goryainov [2024] EWHC 3317 (Ch); [2024] EWHC 2436 (Ch), a US$40m+ 12-day Chancery trial arising from the breakdown of a joint venture involving allegations of dishonesty, concealed income and non-disclosure, obtaining indemnity costs;
advising (led by Fergus Randolph KC) on limitation in deceit claims, including the postponement of time under section 32 of the Limitation Act 1980;
assisting a Member of Chambers with advice on claims arising out of financial market manipulation;
assisting a Member of Chambers with advice on the merits of potential misrepresentation claims against a bank;
assisting a Member of Chambers in Bidzina Ivanishvili v Credit Suisse, an appeal against a Bermuda judgment involving claims in misrepresentation against a bank.

Commodities Disputes

Sebastian’s instructions in this area have included:

acting for an S&P 500 company in a US$100m+ LCIA arbitration (2026) concerning the supply of a soft commodity;
acting (led by Claire Blanchard KC and instructed by HFW) in Moeve Trading SAU v Mael Trading FZ LLC [2026] EWHC 17 (Comm), a US$13m+ action for the price of gasoline and gasoil sold FOB under section 49 of the Sale of Goods Act 1979, concerning the operation of letters of credit and the tender of shipping documents;
acting for a trading company in a US$10m+ set of parallel SIAC and DIAC arbitrations (2025) arising out of a multi-cargo sale of gasoline;
advising (as sole counsel) on a potential ICC arbitration arising from the sale of industrial machinery involving allegations of defective quality (2024);
acting (as sole counsel) for an Ecuadorian supplier on a claim arising from the sale of two container shipments of processed seafood products involving allegations of defective quality (2024);
acting for a trading company in a US$10m+ Swiss-seated arbitration (2023) arising out of the CFR sale of a bulk cargo of iron ore fines, involving alleged non-conformity, certificate and sampling disputes, and the right of rejection;
assisting a Member of Chambers in respect of a US$10m+ ICC arbitration (2022) concerning the sale and exclusive distribution of coal combustion products.

Conflict of laws & private international law

Sebastian has an interest in private international law and came top of his year in conflict of laws at the University of Cambridge. Many of his cases raise jurisdictional and choice of law issues. Examples include:

acting (led by Tim Akkouh KC and instructed by Slaughter and May) in Chugga Chugg v Privinvest [2025] EWHC 585 (Comm), which raised issues of German insolvency law;
acting (led by Mark Howard KC and instructed by Mishcon de Reya) for Nigeria in Nigeria v P&ID, which raised issues of bribery under Nigerian law;
acting (unled) for IndiGo in a successful jurisdiction challenge in the County Court;
assisting Tom Ford in Kinsella v Emasan AG, which raised issues of authority under Swiss law;
assisting a Member of Chambers with advice on proper law in respect of claims arising out of financial market manipulation;
assisting a Member of Chambers in respect of an application for an anti-arbitration injunction;
assisting a Member of Chambers with advice as to the scope of the jurisdiction to stay proceedings under Brussels I Recast in a high-value fraud claim;
assisting a Member of Chambers with advice regarding parallel proceedings in the United States for a declaration of non-liability and the merits of a potential anti-suit injunction.

Energy & natural resources

Sebastian’s instructions in this area have included:

acting (led by Mark Howard KC and instructed by Mishcon de Reya) for Nigeria in Nigeria v P&ID, an eight-week fraud challenge to $11bn+ arbitration awards arising out of a gas processing agreement;
advice and pre-action correspondence (as sole counsel) in relation to a nine-figure claim arising out of the proposed charter or acquisition of a drillship for offshore operations (2025).

Joint venture and post-M&A disputes

Sebastian’s instructions in this area have included:

acting (led by Stephen Houseman KC and instructed by Clyde & Co) in Arbitral v Britannia Financial Group (2025), a Commercial Court earn-out trial, which settled on the first day, arising from the sale of a financial brokerage and concerning the proper construction and operation of deferred consideration provisions in a share purchase agreement, appearing (unled) before Knowles J in an interlocutory application;
acting (led by Tim Akkouh KC and instructed by Candey) in Rogachev v Goryainov [2024] EWHC 3317 (Ch); [2024] EWHC 2436 (Ch), a US$40m+ 12-day trial and 3-day consequential hearing concerning the breakdown and unwinding of a joint venture for the acquisition and redevelopment of a portfolio of Moscow markets;
advising (led by Stephen Houseman KC) on the proper construction and operation of pre-emption rights under a shareholders’ agreement governing a joint venture company.

Shipping & Shipbuilding

Sebastian’s instructions in this area have included:

acting (led by Claire Blanchard KC and instructed by HFW) in Owners of the M/T Harbour Progress v Mael Shipmanagement, intervening in Commercial Court proceedings by shipowners under letters of indemnity issued to procure discharge of cargo;
acting (led by Tim Akkouh KC and instructed by Slaughter and May) in Chugga Chugg v Privinvest [2025] EWHC 585 (Comm), a two-week trial arising out of the termination of a 79.99m superyacht construction contract, involving competing allegations of repudiatory breach, affirmation arising from the shipyard’s continued performance, and the effect of the shipyard’s insolvency on the status and effect of LMAA awards under a refund guarantee, appearing (unled) before Bright J in a post-judgment asset disclosure application (2026);
advice and pre-action correspondence (as sole counsel) in relation to a nine-figure claim arising out of the proposed bareboat charter or acquisition of a drillship (2025);
advice and pre-action correspondence (as sole counsel) in relation to a claim under a ship design services agreement (2025);
acting in a US$10m+ set of parallel commodities SIAC and DIAC arbitrations (2025), involving substantial shipping law issues, including the scope and effect of a competing LMAA arbitration clause in a sub-charterparty between the buyer and seller;
acting in a US$10m+ Swiss-seated arbitration (2023) involving an assigned demurrage claim.

Sport, Media, Art & Entertainment

During pupillage, Sebastian assisted a Member of Chambers with advice in respect of the scope of the regulatory powers of a sports governing body.

Career

2022: Tenant at Essex Court Chambers

2021-2022: Pupil at Essex Court Chambers (supervised by Tom Ford)

2021: Called to the Bar at Lincoln’s Inn

Education

2019-2020: LLM, Harvard Law School

2018-2019: Bachelor of Civil Law (Distinction), University of Oxford

2016-2017: Erasmus, Universiteit Utrecht

2014-2018: Bachelor of Arts in Law (First Class, 4th in year), University of Cambridge

Awards