Mark is a market-leading defence-side competition litigator. He has unsurpassed experience of litigating antitrust damages claims and collective proceedings, having handled many of the leading cases, and has an unmatched record of success.
Working as part of the top-ranked antitrust litigation team at Freshfields, Mark uses his leading experience and tactical acumen to maximise outcomes for clients, as his track record of success attests.
Mark continues to practise a hundred percent alongside serving as the Managing Partner of our London and Dublin offices. He brings a hands-on approach that clients value, delivering forward-thinking strategies that minimise exposure and help clients, including boards and senior stakeholders, understand and manage financial and reputational risk.
With unmatched experience in defending clients from damages actions before the UK courts and Competition Appeal Tribunal (CAT), Mark has played a pivotal role in many of the leading UK competition damages cases. He is particularly known for his work defending opt-out collective proceedings in the CAT, having acted on the defence side of a number of the defining cases.
Mark also advises on competition and antitrust investigations across the UK, EU and beyond, as well as market studies and investigations before EU and UK competition authorities. He has advised on arbitrations involving competition law issues (under ICC and UNCITRAL rules) and has appeared as an advocate before arbitral tribunals.
Mark is a member of the CAT User Group, which advises the CAT on the development of its rules and procedures. In addition, he has previously held roles on the ABA's Antitrust Global Private Enforcement Committee, and has a deep understanding of the global competition and antitrust landscape.
Mark is recognised as a top-ranked practitioner in the leading directories. He is listed as a Global Elite Thought Leader in both Competition and Firm Management by Chambers. In 2019, peers worldwide voted him Global Competition Review’s Litigator of the Year (for which he has again been shortlisted in 2025), and he was featured in The Lawyer’s ‘Hot 100’ list of leading lawyers for 2024.
- Defending Mastercard in the leading Merricks v Mastercard collective proceedings before the UK’s CAT, Court of Appeal and Supreme Court, including in relation to the collective settlement of the proceedings. Reportedly the largest damages claim ever brought in the UK, the claim has been pivotal in shaping the approach to all UK antitrust class actions.
- Mark is also defending Mastercard in the separate Commercial Cards collective proceedings in the CAT and in the Merchant Umbrella Proceedings.
- Representing London and South Eastern Railway in the Gutmann v LSER collective proceedings concerning rail tickets, the first standalone and first alleged abuse of dominance related collective proceedings brought in the CAT under the UK's competition class action regime.
- Acting for Govia Thameslink Railway in the Gutmann v GTR and Boyle v GTR opt-out collective proceedings, also standalone abuse claims concerning rail tickets.
- Acting for ABB in the leading BritNed v ABB High Court action and in the Court of Appeal. The case was the first cartel damages follow-on claim to go to final judgment at first instance, and on appeal, in the UK. ABB defended the claim successfully at trial and prevailed on all points in the October 2019 Court of Appeal judgment. Mark has also represented ABB in a range of other damages claims relating to the gas insulated switchgear, power transformers and power cables cartels.
- Successfully defending Infineon Technologies in the UK High Court and Court of Appeal in the Gemalto v Infineon & Ors High Court follow-on damages claim arising out of the European Commission's infringement decision in relation to smartcard chips. The case is now a leading authority on limitation.
- Acting on numerous other competition litigation proceedings, and in investigations, in a range of markets and sectors including water, automotive, technology, media, financial services, sport, transport and pharma.

