Jacquelyn MacLennan

Partner, Brussels, London


“A superb practitioner and very good public speaker who always looks for solutions.”
Chambers Europe 2015


Jacquelyn MacLennan offers a wealth of experience for clients worldwide, representing leading multinational corporations, governments and trade associations.

She focuses on EU competition law, and clients benefit from her experience and insight in developing strategy and running major international cartel investigations, as well as advising on complex distribution problems and licensing arrangements, abuse of dominance cases, mergers and joint ventures.

Jacquelyn is a core team member of the firm's Business & Human Rights Interest Group and advises on a wide range of issues related to ESG and sustainability, including corporate supply chain compliance, disclosure requirements, and Business & Human Rights issues generally.

She also advises on EU customs and trade law, international sanctions, and EU regulatory requirements, notably in respect to product safety and environmental regulation.   

With an impressive track record of experience and know-how, Jacquelyn litigates regularly before the EU and UK courts, and represents clients before the European Commission.

Jacquelyn has accumulated substantial management experience over her career; she has been a Member of the Partnership Committee (the main governance body) of White & Case, a Member of the Executive Committee (responsible for the firm's strategy), and Executive Partner heading the Brussels office. In October 2015, she became the Global Pro Bono Practice Leader.

Clients describe Jacquelyn as "excellent – an industry leader in antitrust matters" and "commercially-minded and solution-oriented." (Chambers Europe, 2016)

Bars and Courts
Solicitor in Scotland
Notary Public
Brussels Bar
Diploma in Legal Practice
University of Edinburgh
LLB (Hons)
University of Edinburgh


Toshiba—global proceedings—appeal to Court of Justice of the EU and current appeal to General Court
Jacquelyn is representing Toshiba Corporation in multijurisdictional proceedings concerning Gas Insulated Switchgear. This involved a successful appeal of the original European Commission decision fining Toshiba €90.9 million for participating in a global cartel to the European General Court—where the Court annulled in full the fine on Toshiba—and a further appeal to the Court of Justice of the EU. An appeal to the General Court is now pending of the new, lower, fine imposed by the Commission.

Major multinational—customs issue
Jacquelyn represented a major multinational in successful proceedings involving the World Customs Organization, European Commission, national customs authorities and national courts concerning the classification of insulated-gate bipolar transistors.

Toshiba—preliminary ruling to Court of Justice of the EU
Jacquelyn represented Toshiba in a seminal preliminary ruling to the European Court of Justice, which established the principles governing the scope for parallel proceedings by national competition authorities and the European Commission.

US chemicals multinational—customs matters
Jacquelyn advises a US chemicals multinational on a range of high-level customs matters, including rules of origin, tariff quotas and special customs procedures (such as temporary importation).

Toshiba—appeal to European General Court
Jacquelyn is representing Toshiba in an appeal to the Court of Justice of the EU of the Commission Decision in Cathode Ray Tubes (CRT) used for TVs and computer monitors, regarding the conduct of a JV for which it was held liable, having successfully had liability and a fine of €28 million quashed by the European General Court.

Multinational corporations—environmental issues etc.
Jacquelyn is advising major multinational corporations on environmental issues at EU and at national level, as well as handling compliance issues, including inspections by competent authorities, and product recalls.

Toshiba—appeal to Court of Justice of the EU
Jacquelyn represented Toshiba in an appeal to the Court of Justice of the EU against a Commission Decision finding a home market protection agreement in Power Transformers.

Speaking Engagements

Speaker, "Sustainable Trade: EU Developments", White & Case webinar, 21 May 2021

Session chair, "Sustainability and competition law", 3rd UCL/White & Case Competition Law Conference, 22 April 2021

Speaker, Pro Bono Chambers Europe Awards 2021, Chambers & Partners, 22 April 2021

Judge, World Championship Semi-Finals, Philip C. Jessup International Law Moot Court Competition, 17 April 2021

Panel discussion leader, Edinburgh University Brussels Society Careers Day, 12 April 2021

Panel discussion leader, Philip C. Jessup International Law Moot Court Career Panel, 20 March 2021 

Panel moderator, "Digital Antitrust Reforms in the EU and the US: What role for the courts?", Concurrences 2nd Digital and Competition Conference, 9 March 2021; Jacquelyn also interviewed Giovanni Pitruzzella (Advocate General, CJEU) for the conference (transcript available here)

Speaker, EU Environment, Social and Corporate Governance Regulatory Developments, including the EU Public Consultation on Sustainable Corporate Governance, CRLA Committee Meeting, 3 February 2021

Panel moderator, "A global standard for Mandatory Due Diligence: EU leadership towards a more sustainable world", European Justice Stakeholder Foundation's 5th plenary meeting, 3 December 2020

Speaker, "Brexit: How Hard Can it Be?", webinar, 1 December 2020

Panel moderator, "Collaboration & Cooperation in Time of Crisis", Advanced EU Competition Law: Competition Law in the Digital Era, Informa, 24 November 2020

Speaker, "Civil Liberties Under Attack: Protecting Privacy and Freedom of Expression", Thomson Reuters Foundation Trust Conference, 11 November 2020

Panel moderator, "Addressing Systemic Racism", PILnet Global Forum, 21 October 2020

Speaker, "What can, and should, the US and the EU antitrust authorities do about tech giants?", Concurrences panel discussion, Paris, 6 October 2020

Panel moderator, "Legal strategies challenging immigration detention: the preliminary reference procedure before the Court of Justice of the EU", PICUM webinar, 30 June 2020
Speaker, "The EU/UK Future Relationship after Brexit", webinar, 13 June 2020

Speaker, "Why people work for free? The Pro Bono phenomenon", Citizen Lobbyist podcast, 4 May 2020

EJSF – 4th annual plenary: moderated key panel discussion "Rights under threat – how can the EU Fundamental Rights Charter work better for citizens?", European Economic & Social Committee (EESC), 19 November 2019, Brussels

TRUST Conference "Digital rights: the new frontier of human rights?" 14 November 2019, Queen Elizabeth II Centre, London

"Chambers D&I Pro Bono Summit panel", fireside chat at the Chambers Diversity & Inclusion European Pro Bono Seminar, 6 November 2019, Amsterdam, Netherlands


"The challenge of ESG for EU competition law", IFLR, February 2021

"EU Competition Law and EU Charter of Fundamental Rights: An Evolving Partnership", foreword to E-Competitions Special Edition "ECHR & Competition law - an overview of EU and national case law", 3 December 2020 (with Bram Vereecken and Aron Senoner)

"The Constitutional Dimension of Case C-673/16 Coman on the Prohibition of Discrimination on the Basis of Sexual Orientation: The Role of Fundamental Rights in Interpreting EU Citizenship", Columbia Journal of European Law, Issue 2, Spring 2020 (with Angela Ward)

Citizenship and Incremental Convergence with Fundamental Rights, Case Note on Coman and Others (Case C-673/16 ECLI:EU:C:2018:385), Cambridge Law Journal, Volume 78 Issue 2, July 2019.

"Innocent until proven guilty – Five things you need to know about killer acquisitions", Comp Law, KNect365, 3 May 2019, (co-author with Tilman Kuhn and Thilo Wienke)

Vertical restraints in an online world: competition authorities gear up their enforcement approach in the digital economy, Competition Law Journal, Vol. 18, No. 1, April 2019 (co-author with J. Jeram and M. Israel)

Co-author, European Union chapter, The Environment and Climate Change Law Review, 3rd edition, 2019 (co-author with Tallat Hussain)

Environment and climate change in the European Union, Lexology Navigator, June 12, 2018, (co-author, with Genevra Forwood, Emma Bichet, Julio-Felipe Pantazis)

European Union chapter, Getting the Deal Through – Risk and Compliance Management, 17 June 2017, (co-author with Stuart Willey)

The Great Repeal Bill – examining the impact on UK international trade, Lexis®PSL, May 22, 2017

Toshiba v. Commission – How (not) to Prove Awareness, and Decisively Influence People, Competition Policy International, August 2016, (co-author, with Aqeel Kadri)

Competition Law in China – an ant on the move?, The Lawyer, May 2012

EC Competition Law Developments, Oxford Yearbook of European Law, 1997–1998, 1999–2000, 2001–2002, 2003–2004, 2005–2006, 2007–2009, 2010, (co-author)

Awards and Recognition

Chambers Europe Awards 2022, Commended, (Private Practice) Diversity & Inclusion: Outstanding Contribution

Women in Antitrust 2021, Global Competition Review

Who's Who Legal: Competition, 2019

Leading Lawyer: Competition/European Law — Belgium, Chambers Europe 2019

Recommended: Competition: EU and global – Belgium, Legal 500 EMEA 2019

Recommended: Customs, trade, WTO and anti-dumping – Belgium, Legal 500 EMEA 2019

Leading Lawyer: Environment: EU Regulatory — Europe-wide, Chambers Europe 2019

Top Ten Innovative Lawyers in Europe – FT Innovative Lawyers 2018

100 Elite Women in Antitrust, Global Competition Review 2016

Best in Competition & Antitrust, Euromoney Women in Business Awards – Europe, 2016 and 2017

Recommended: Not-for-profit – Belgium, Legal 500 EMEA 2018

Leading Lawyer: International Trade/WTO — Europe-wide, Chambers Europe 2017

Leading Lawyer: International Trade/WTO — Belgium, Chambers Europe 2017

Honorary Fellow, Europa Institute, University of Edinburgh

Best Business Anticompetitive Practices Article, 2012 Antitrust Writing Awards

Member of Chatham House

Member of the Environmental Law Network International (elni)

Member of IBA Pro Bono Committee and Human Rights Law Committee

Member of PILnet's Pro Bono Leadership Committee

Member of the ELI-FRA Business and Human Rights Project Team