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Pat Treacy


Pat Treacy

Senior Partner
+44 (0)20 7400 8373
+32 2 400 6232

Pat has specialised in EU law and competition law for almost 30 years and has been involved in landmark cases at EU and national level. In addition to her expertise across the range of competition law, she has particular strengths in advising on the complex legal and policy issues arising where competition law and intellectual property law intersect. Consequently, clients in high technology sectors including life sciences and TMT seek her advice regularly.

Pat represents clients before the competition authorities and the courts, whilst also advising on competition law issues in complex agreements (including settlement, R&D and licensing agreements).  Pat advises many of the Firm's clients on the competition law responsibilities affecting dominant companies. She and her team assist clients with competition compliance programes and preparation for "dawn raids", having supported clients through such dawn raids and their aftermath.  Pat is also a frequent commentator on the intersection of competition and IP law as featured in the blog The CLIP Board.

Pat was appointed Deputy High Court Judge in September 2018, and will serve in the Chancery Division for a term of four years. The appointment is on a part time basis, and Pat continues as a Partner alongside this role. Pat is a member of the Competition Law Association; the UK Association of European Lawyers; and the Competition Section of the Law Society.  She is on the editorial board of the Journal of Intellectual Property Law and Practice and Competition Law Insight. Pat lectures and writes widely on topical issues. She also teaches the competition law module on the University of Oxford Postgraduate Diploma in Intellectual Property Law and Practice course.


  • MA Law, University of Cambridge
  • Qualified 1986
  • Admitted in Republic of Ireland (non-practising)
  • Partner 1996
  • Senior Partner 2018

Recommended for

  • Best Lawyers in the United Kingdom for Competition Law and Information Technology Law (2019/2018/2017/2016/2015)

  • Competition/ European Law: Non-contentious - Chambers and Partners (2019/2018/2017/2016/2015)

  • Competition Law: Litigation - Chambers and Partners (2019/2018)
  • Competition litigation (leading Individual) - Legal 500 (2019/2018)
  • EU and Competition - Legal 500 (2019/2018/2017/2016/2015)
  • Competition litigation - Legal 500 (2019/2018/2017/2016/2015)
  • Competition - Who’s Who Legal Worldwide Thought Leaders (2019)
  • Competition - Who’s Who Legal (2019/2018/2017)
  • Competition and Antitrust: Leading practitioner - Expert Guides: Women in Business Law (2018/2017/2015)

  • Pharmaceuticals and biotechnology - Legal 500 (2017)

  • Competition Team of the Year - The Lawyer Awards (2017)
  • Non IP Litigation/Competition/Antitrust - LMG UK Life Science Stars (2015)

Pat Treacy assists clients with both contentious and non-contentious competition law matters. She represents defendants in abuse of dominance cases and market investigations. Treacy also acts for life sciences clients on the competition law aspects of patent cases. She “provides highly bespoke advice in a measured and digestible way and is a pleasure to deal with.” - Chambers and Partners 2019

Practice head Pat Treacy is recommended as ‘the go-to competition counsel in Europe for IPinnovation related matters, delivering outstanding work’." - Legal 500 2019/2018

Pat Treacy advises clients from the TMT and life sciences sectors on the interface between competition law and IP. Commentators describe her as a "strategic thinker who is very business like, gets straight to the point and provides clients with options." She acted for Cousins Material House on a claim of abuse of dominance brought against Swatch. - Chambers and Partners 2018

"‘instinctive litigator’ Pat Treacy successfully defended Google in High Court proceedings regarding the client’s dominant position in the area of online mapping. Additionally, Treacy acted for Google in the high-profile claims regarding the client’s practice of online shopping and price comparison services." - Legal 500 2017

"Practice head Pat Treacy is advising longstanding client Sony Interactive Entertainment Europe on resisting a potential interim injunction application in relation to abuse of dominance allegations." - Legal 500 2017

"Pat Treacy is described by clients as 'a fantastic lawyer: she has a good understanding of business dynamics, is always calm and collected and provides advice in a digestible way.' She acts on a broad range of competition law mandates, with particular expertise in matters at the intersect of IP and competition law." - Chambers and Partners 2017

"...competition expert Pat Treacy." Legal 500 2016

"Practice head Pat Treacy, who ‘skilfully translates the complexities of competition law into pragmatic legal advice’, advised Kimberly-Clark during an investigation launched by the Groceries Code Adjudicator." - Legal 500 2016

"Pat Treacy is the head of department at Bristows LLP and has particular knowledge of cases which span competition law and IP law. She has sector-specific knowledge within the life sciences and TMT sectors." - Chambers and Partners 2016

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