William Leslie

Antitrust & Foreign Investment Partner, Brussels

“I advise multinational corporates and other institutions on global competition, foreign investment and regulatory laws, with significant experience in the financial infrastructure, FMCG, life sciences, tech and telecoms spaces. I combine an in-depth understanding of these frequently evolving areas of law with a pragmatic approach to provide clients with creative and practical solutions for their most complex legal challenges."


Education and qualifications

Published works


Will is a Partner in the Antitrust & Foreign Investment Group and co-heads the firm’s technology sector team. 

Will advises multinational corporates and other institutions on all areas of EU competition, foreign investment and regulatory laws. He has a broad range of experience in EU and UK competition law, notably in relation to complex M&A, abuse of dominance, state aid and regulatory price control matters.

Will has assisted clients with merger control filings and antitrust proceedings across multiple jurisdictions, with particular experience before the European Commission and the UK’s Competition & Markets Authority. His experience spans many industry sectors, with a particular focus in the financial infrastructure, FMCG, life sciences, tech and telecoms spaces.  

During his career Will has worked in Brussels, London and Paris and has had client secondments with HSBC and Unilever. 

Work highlights

  • Intel: advising Intel on the global merger control proceedings for the sale of its NAND and SSD business to SK Hynix
  • Vodafone / Telecom Italia / INWIT: advising Vodafone on the European Commission’s parallel antitrust and merger control investigations into its network sharing arrangements with Telecom Italia, including the merger of its passive tower infrastructure in Italy into INWIT.
  • Abuse of Dominance Investigations (Exclusivity): advising a multinational corporate in relation to investigations by authorities in the EU into alleged abuse of dominance as well as the subsequent appeals processes.
  • Google Shopping: advising Kelkoo in its response to Alphabet’s appeal before the Court of Justice of the European Union.
  • Deutsche Börse / LSE: advising Deutsche Börse on European Commission’s Phase II investigation of its proposed €21bn merger with the London Stock Exchange Group plc.
  • Novartis / GSK: advising Novartis in obtaining EU and global merger control clearances for its $16bn oncology/vaccines asset swap with GSK, including the partnership divestment of two pipeline pharmaceuticals.

Education and qualifications

Will holds an M.A. history and an M.Phil. in international relations from Cambridge University as well as a master’s in EU competition law from King’s College, London.

Published works

Will regularly publishes on competition law. Recent examples include:

Christian Ahlborn, Gerwin van Gerven and Will Leslie “Bronner revisited: Google Shopping and the Resurrection of Discrimination Under Article 102 TFEU” JECLAP, Volume 13, Issue 2, 2022

Gerwin van Gerven, Annamaria Mangiaracina, Will Leslie, Lodewick Prompers, “Data and privacy in EU Merger Control” in GCR’s Digital Markets Guide - First Edition (2021)

Christian Ahlborn and Will Leslie, '“Jack of all trades, master of none”: the ever-increasing ambit of the market investigation regime’ in A. MacCulloch, B. Rodger and P. Whelan (eds), The UK Competition Regime: A Twenty-Year Retrospective (OUP: 2021)