OVERVIEW

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.

EDUCATION

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

BAR ADMISSIONS

Solicitor of the Senior Courts of England and Wales, 2009
Admitted to the Brussels Bar, 2019
Higher Rights (Civil Advocacy)

AFFILIATIONS

Member - W@Competition organising committee

WHAT OTHERS SAY

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 and 2025 in their list of 500 Global Plaintiff Lawyers for Competition law, esp. plaintiff

Experience

Antitrust/Competition

Lesley has been one of the lead partners on the Hausfeld team dealing with:

The opt-out collective action filed with the CAT on behalf of an estimated 19.5 million eligible UK users of smartphones and tablets running on Google’s Android operating system relating to excessive and unlawful charges on purchase in the Google Play store. The claim alleges that Google unfairly restricts consumers from accessing potential competition from other app distributors, by requiring smartphone manufacturers to pre-install a bundle of Google’s proprietary apps and services including the Google Play Store as well as imposing other contractual and technical restrictions.
The representative collective action filed with the CAT on behalf of some 19.6 million eligible UK iPhone and iPad users relating to excessive and unlawful charges by the Apple App Store. The claim alleges that Apple’s conduct violates section 18 of the UK Competition Act 1998 and Article 102 of the Treaty on the Functioning of the European Union.
Representing Foundem in an abuse of dominance claim against Google linked to the EC's infringement finding in relation to Google Shopping
Acting for the proposed class representative, consumer advocate Julie Hunter, in collective proceedings filed against Amazon.com, Inc. seeking damages on behalf of UK consumers for alleged anticompetitive conduct in relation to Amazon’s ‘Buy Box’.
Air Cargo, bringing claims in the High Court on behalf of some 100 corporate groups against British Airways in relation to the worldwide cartel in air freight surcharges - one of the largest and lengthiest competition damages action brought in Europe to date. The claim settled after a complex 6-month mediation process in December 2018.

Technology & Data Breach

Lesley was one of the partners leading the team which:

Filed a CPR 19.6 representative action brought on behalf of Duncan McCann, on behalf of up to 5 million British children aged under 13 and their parents in the High Court – alleging that YouTube’s methods of targeting underage audiences and harvesting their data constitute major violations of the UK Data Protection Act and the EU’s General Data Protection Regulation (GDPR), both of which were designed to protect citizens’ privacy rights.