John Messent’s practice covers all aspects of UK and EU competition law, as well as the UK’s national security and public interest regimes and global foreign investment controls.

John has represented clients on complex multinational matters, transactional and behavioral, before the UK Competition and Markets Authority, the European Commission, UK sectoral regulators, the UK Investment Security Unit, and the UK and EU Courts. He also helped draft the Competition and Markets Authority’s guidance on merger review, Competition Act investigations, and criminal cartel prosecutions during a six-month secondment. 

John has secured clearance for >£100 billion of transactions under the UK national security regime since 2022 in non-published matters, for large multinational conglomerates and global investors, including in-depth ISU review.

He became a partner in 2025.

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Notable Experience

  • Synopsys, a global leader in EDA and semiconductor IP, in its proposed $35 billion acquisition of Ansys.

  • CSL Vifor on the CMA’s Competition Act investigation into intravenous iron treatments.

  • IBM on its €2.1 billion acquisition of Software AG’s Super iPaaS enterprise technology platforms.

  • Thales on the CMA’s Phase 2 conditional clearance of the €1.7 billion sale of its GTS business to Hitachi Rail.

  • Broadcom on its $69 billion acquisition of VMware Inc.

  • Veolia on the CMA’s Phase 2 conditional clearance of its €12.9 billion acquisition of Suez.

  • OpenText on its US$6 billion recommended offer for Micro Focus International plc.

  • Allied Universal on its £3.8 billion recommended offer for G4S plc and other transactions.

  • Ecolab on the CMA’s Phase 2 investigation of its acquisition of Holchem, and in its application to the Competition Appeal Tribunal for review of the CMA’s decision to unwind the transaction.

  • Essilor on its $24 billion merger with Luxottica.

  • Cascade Investment in the approximately $4.7 billion recommended cash acquisition of Signature, as part of a consortium with Blackstone and Global Infrastructure Partners.

  • Walgreens Boots Alliance on its $6.5 billion strategic transaction with AmerisourceBergen Corporation.

  • Ryanair in the European Commission’s Phase 1 clearance of its acquisition of Laudamotion, its bids for Aer Lingus, and various other UK and EU antitrust matters.

  • Whirlpool in the EC’s Phase 2 clearance of the sale of its Embraco compressor business to Nidec.

  • HCA in its successful appeal of the CMA’s Private Healthcare Market Investigation and in the remitted Market Investigation before the CMA.

  • Dassault Systèmes in its successful defence against a complaint to the EC regarding alleged abuse of dominance, and then before the General Court in the appeal by Contact Software.

  • The Coca-Cola Company in connection with various UK and EU antitrust matters.

  • Sony Music in connection with various UK and EU antitrust matters.

  • American Express in connection with various UK and EU antitrust matters.

  • J-Power Systems in relation to the European Commission’s investigation into producers of high-voltage power cables, in which JPS achieved a leniency discount of 45%.

  • Sony Corporation in relation to the European Commission’s investigation into producers of rechargeable batteries, in which Sony received a leniency discount of 50% and a further settlement discount of 10%.

  • Recticel in relation to the European Commission’s investigation into producers of flexible polyurethane foam, in which Recticel achieved a leniency discount of 50% and a further settlement discount of 10%.

  • OpenText before the OFT on its $1.165 billion acquisition of GXS.

  • Lafarge in connection with its UK building materials joint venture with Anglo American’s Tarmac business.

  • Various other companies in relation to unannounced antitrust investigations by the European Commission and the CMA.

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Publications

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