“Ollie Swain is intelligent and hard working, he is cerebral without letting this get in the way of practical advice.”

The Legal 500 UK 2023


Olivier is a commercial litigation senior associate with experience in investigations, advisory work and management of multi-jurisdictional proceedings.

He regularly acts in High Court and Court of Appeal proceedings and has experience of litigation, mediation, and ADR in both London and Dublin.

Olivier has also expertise in complex high-value LCIA, ICC and ad-hoc arbitrations, as well as arbitration appeals. His key industry sectors include banking and financial services, real estate and energy and natural resources.

Olivier is a ‘Recommended Lawyer’ for commercial litigation and banking litigation in The Legal 500 UK 2023 Guide, and is described as “terrific“, “clever and strategic“. He is also described as “intelligent and hard working,” and a commentator remarks that “he is cerebral without letting this get in the way of practical advice.

Prior to joining Signature, Olivier was a litigation and dispute resolution associate at Arthur Cox (a leading Irish law firm) and before that he trained at the London office of international law firm Taylor Wessing.

Olivier is a native French speaker and proficient in German. He is dual-qualified and admitted in both England and Wales and Ireland. Olivier qualified in England and Wales in 2016 and was admitted to the roll of solicitors In Ireland in 2018.

Olivier is a member of the London Solicitors Litigation Association (LSLA) and Junior LSLA.


Commercial Litigation

  • Acting in a business-critical internal investigation conducted by a blue-chip company.
  • Acting for a state entity in High Court proceedings against a property developer and advising on related contentious data subject access requests.
  • Advising a leading property development company in multiple judicial review proceedings and Commercial Court proceedings, including related appeals.
  • Advising a leading global manufacturer in a crisis management scenario.
  • Representing a listed chemicals company on the management of multi-jurisdictional asset tracing proceedings.
  • Representing the liquidators of an investment fund in multi-jurisdictional proceedings against an investment bank.

International Arbitration

  • Advising a state-owned resources company in LCIA arbitrations involving a major bank and related appeals in the High Court and Court of Appeal.
  • Advising a property developer in multiple ICC arbitrations and assisting with the management of related European court proceedings.
  • Advising a parastatal entity in ad hoc proceedings against a state agency concerning the implementation of an investment-related agreement.


  • Advising leading investment banks and funds on litigation-related aspects of loan portfolio sales, dispute resolution mechanisms, and data subject access requests.
  • Advising commercial entities on settlement of incentive-related disputes, disputed debts, and other business disputes.


What to expect from the UK’s new Economic Crime Bill – Law360 – 3 November 2022

Landmark Supreme Court judgment on the creditor duty – The Law Society Gazette – 14 October 2022

Latest news

All news