A qualified solicitor-advocate, Lesley focuses on - often complex and cross-border - competition damages litigation.
Expertise
Lesley has extensive experience in managing multi-party claims and litigating against multiple defendants. She possesses considerable litigation experience in both the Competition Appeal Tribunal and the English High Court. Besides her expertise in dealing with follow on competition damages, she also manages abuse of dominance disputes, often against global corporates including tech giants.
She uses her expertise in European and Competition law together with her strong commercial acumen to focus and narrow the areas of dispute and to achieve compensation for businesses that have suffered losses as a result of illegal anticompetitive conduct.
Clients
Lesley advises and represents major corporate clients across a broad range of sectors and industries. She understands that litigation can be an unwelcome distraction for a business and makes sure that her clients achieve the best result with minimum risk and disruption.
Diploma in French Law, Université de Grenoble, France
LLB (Hons) Law and French Law, University of Aberdeen
LLM in European Law, College of Europe, Bruges
Solicitor of the Senior Courts of England and Wales, 2009
Admitted to the Brussels Bar, 2019
Higher Rights (Civil Advocacy)
Member - W@Competition organising committee
Chambers UK
Lesley Hannah is “very diligent, thorough and careful”; “it's her technical knowledge; she is very technically astute” and “I like working with her a lot; she is very experienced”; “I feel very comfortable talking to her about cases.” - Competition Law: Private Enforcement: Claimant, Chambers UK and Chambers Global, 2025
Lesley Hannah is "a competent and proactive professional; she demonstrates deep knowledge of her area of expertise.” - Group Litigation: Claimant, Chambers UK, 2025
Lesley Hannah “demonstrates great expertise in the digital sector, which is a growing area for antitrust scrutiny” and “She's definitely carving out real expertise for competition claims against big tech companies.” - Competition Law: Private Enforcement: Claimant, Chambers UK, Chambers Europe and Chambers Global, 2024
Lesley Hannah “is very impressive and completely across the law in her area. She has fantastic experience in competition cases” and “is approachable and friendly with an ability to explain complex legal matters in a clear and simple way”; “is incredibly knowledgeable and insightful. She is a strategic thinker with excellent understanding of the big picture, the details of the case and how they fit together.” - Group Litigation: Claimant, Chambers UK, 2024
'Lesley Hannah is super-smart and unerringly focused on strategic outcomes. Her advice is clear, direct and well thought out... [she] combines technical excellence with innovative thinking and a fearless attitude to take on the most powerful defendants.' - Competition Law: Private Enforcement: Claimant - Chambers UK, 2023
Legal 500 UK
'Next Generation Partner', Lesley is ‘clear-minded, determined, and able to juggle the many tactical and legal challenges of large-scale litigation.’ - Competition Litigation, 2025
'Leading Individual', Lesley brings 'extensive experience in collective damages and abuse of dominance claims to the team.’ - Group Litigation: Claimant, 2025
'Next Generation Partner', Lesley is ‘extremely competent and imaginative'. - Competition Litigation, 2024
'Leading Individual', Lesley is 'highly knowledgeable as well as being battle hardened in the leading cases.’ - Group Litigation: Claimant, 2024
Ranked as a "Next Generation partner, she is exceptional" and "has already established herself as one of the top practitioners in this area and is excellent..." Lesley is a "class act and constantly spearheads the most significant competition disputes." - Competition Litigation, 2023
Ranked as a 'Next Generation Partner': ‘Experienced, calm, knowledgeable, strategic, innovative. Lesley has a determined yet approachable manner. As a client you know from the outset she is on your side and is going to fight your corner.' - Competition Litigation, 2022
Ranked as a 'Next Generation Partner': ‘Lesley Hannah is an excellent lawyer, who combines a great eye for detail with strategic and tactical vision for each case.’ - Competition Litigation, 2021
'Lesley Hannah, who is particularly prominent in the technology sector...' - Competition Litigation, 2021
‘A great lawyer’ - Competition Litigation, 2019
Lesley was described as having ‘a bright future’. – Competition Litigation, 2018
Who's Who Legal
Recognised in 2023 and 2024 as a Global Leader in Competition Plaintiff: "Lesley is a very impressive operator, with particular expertise in tech cases."
“Lesley Hannah is celebrated for her incisive handling of multi-party competition claims and deep knowledge of abuse of dominance disputes”. Recognised as a Global Leader for Competition Plaintiff in the 2021 edition of Who’s Who Legal ‘Global Leaders 2021’.
Best Lawyers
Lesley has been recognised for Competition Law in the 'United Kingdom Best Lawyers' 2024 and 2025 edition.
Lawdragon
Lesley was recognised by Lawdragon in 2024 in their list of 500 Global Plaintiff Lawyers for Competition law, esp. plaintiff
Lesley has been one of the lead partners on the Hausfeld team dealing with:
Lesley was one of the partners leading the team which:
Lesley Hannah is a competent and proactive professional; she demonstrates deep knowledge of her area of expertise.
Lesley Hannah is very diligent, thorough and careful.
Lesley Hannah is the person you would want running your case - clear-minded, determined, and able to juggle the many tactical and legal challenges of large-scale litigation.
Lesley is very impressive and completely across the law in her area. She has fantastic experience in competition cases. Lesley is approachable and friendly with an ability to explain complex legal matters in a clear and simple way. She is incredibly knowledgeable and insightful. She is a strategic thinker with excellent understanding of the big picture, the details of the case and how they fit together.
Lesley is extremely competent and imaginative.
Lesley Hannah is super-smart and unerringly focused on strategic outcomes. Her advice is clear, direct and well thought out... [she] combines technical excellence with innovative thinking and a fearless attitude to take on the most powerful defendants.
Lesley Hannah has already established herself as one of the top practitioners in this area and is excellent.
Experienced, calm, knowledgeable, strategic, innovative. Lesley has a determined yet approachable manner. As a client you know from the outset she is on your side and is going to fight your corner.
An excellent lawyer, who combines a great eye for detail with strategic and tactical vision for each case.
Lesley Hannah, who is particularly prominent in the technology sector...
A great lawyer.
Lesley was described as having 'a bright future'.
