United Kingdom

The following is part of our annual publication Selected Issues for Boards of Directors in 2026. Explore all topics or download the PDF.

Antitrust in 2025 was marked by policy developments and antitrust enforcement that, while remaining aggressive, became less overtly anti-business. The U.S. continued a number of cases from the Biden administration, but became more open to settlements, while continuing implementation of the new and more burdensome HSR merger notification form and of the more aggressive and less economically focused 2023 Merger Guidelines. The European Commission conducted a series of DMA enforcement actions and launched a broad-sweeping consultation on the Merger Guidelines. The UK CMA continued a tack toward a more restrained approach to enforcement, taking greater account of growth and suggesting it would allow greater flexibility in merger remedies. The Chinese State administration for Market Regulation started to intervene in transactions below the filing thresholds and continued to keep antitrust in its toolbox for tackling geo-political tensions.

2025 was a fascinating year for UK competition and consumer enforcement, with the CMA changing its policies and practices in a number of areas. Our Year in Review summarises the most important developments of the past year and what we expect in 2026, as the CMA implements its reworked procedures for merger and market cases, begins to use its new consumer fining powers, and imposes digital conduct requirements for the first time. We also anticipate a Government consultation on significant changes to the decision-making model for mergers and markets.

On 16 October 2025, the CMA launched a public consultation on its draft revised Merger Remedies Guidance (the Draft Guidance).[1]  The revision reflects the Government’s call for a more business-friendly, pro-growth approach to merger control.[2]

The UK Competition and Markets Authority (CMA) has cleared the Vodafone/Three[1]merger subject to behavioural remedies. The transaction will bring together two of the four largest UK mobile network operators and potentially transform the UK telecoms landscape. The CMA’s approval decision comes against the backdrop of widespread scepticism of consolidation in the mobile telecommunications sector across Europe.  It also departs from the CMA’s previous policy of seeking structural remedies to address competition issues and blocking problematic deals where no structural remedy could be found.

In this episode of Cleary Gottlieb’s Antitrust Review podcast, host Nick Levy is joined by a panel featuring Jackie Holland, Cleary partner and former Senior Director of the UK Office of Fair Trading; Ricardo Zimbrón, former Director of Mergers at the Competition & Markets Authority and currently a partner at Cleary; Alexander Baker, CEO, Fingleton; and John Gray, Partner, FGS Global, to discuss the implications of the new Labour Government for competition enforcement and practice in the UK. Their conversation covers an array of topics, including the new government’s growth agenda, the role of politics in antitrust enforcement, merger control, consumer protection, digital regulation, and much more.