Competition Law: A London (Firms) Overview

Introduction

The practice of competition law in the UK is changing in three important ways: changes to the law itself; changes to the public and private enforcement of the law; and changes in the way practitioners are advising on the law.

Changes to the Law

The primary legislative change is the Digital Markets, Competition and Consumers Act (“the Act”), which entered into force in early 2025. As well as various changes to the core competition laws, the Act created two entirely new regimes, so expanding the scope of the laws on which UK practitioners now advise. 

The first regime is the digital markets regulatory regime, which confers powers on the UK’s primary competition authority, the Competition and Markets Authority (CMA), to designate large digital firms as having “Strategic Market Status” (SMS) – and then to design bespoke conduct requirements for SMS firms to meet standards of fair-dealing, open choices and trust and transparency. As of November 2025, the CMA has designated Google and Apple as having SMS in mobile ecosystems, and Google in search and search advertising, and is considering various proposals for conduct requirements to regulate their conduct in these markets.

The second regime confers powers on the CMA to enforce consumer protection laws directly, ie, without having to apply to the courts, and to impose significant fines of up to 10% of an infringer's group worldwide turnover. This brings consumer protection law enforcement in line with enforcement of the Act prohibitions on anti-competitive agreements and conduct, making compliance with consumer protection law a comparable risk factor for businesses. Although the underlying consumer protection laws are largely unchanged, most UK competition lawyers have historically advised on them only rarely, as relatively weak enforcement resulted in limited demand for advice. That situation has now changed. The CMA recently launched investigations into eight businesses for suspected infringements of consumer protection laws, mostly relating to the ways in which they present prices to consumers. 

It is expected that these developments will result in more businesses seeking advice on compliance with the consumer protection and digital regulatory regimes, as well as representation in legal challenges and complaints. As the CMA’s investigative procedures under these regimes and the level of sanctions are closely modelled on its competition law investigations, clients are turning to competition lawyers for that advice.

Changes to Public and Private Enforcement of the Law

The CMA’s approach to public enforcement of competition law has changed significantly in the last year. Under pressure from the UK government, the CMA has adopted an approach that is more focused on supporting economic growth and investment, in particular by improving the pace, proportionality, predictability and process of its investigations and decisions (referred to by the CMA as the “4 Ps”). This is particularly evident in its merger control functions, with earlier engagement with merging parties and less focus on speculative potential competition concerns, leading to swifter decisions. The CMA has also revised its guidance on merger remedies to signal a greater openness to behavioural remedies to enable conditional clearance of mergers that would otherwise be blocked, including in Phase 1 merger reviews. Behavioural remedies that enhance investment, innovation and economic growth may now receive a more sympathetic hearing, as demonstrated by the Vodafone/Three four-to-three mobile merger, which was cleared subject to conditions requiring the merged company to invest in improving mobile coverage across the country. In contrast to its 2023 decision in Microsoft/Activision, in which the CMA required stricter remedies than other major international competition authorities, the CMA is now focusing enforcement on mergers with effects that are specific to the UK and is more amenable to accepting remedies that have been agreed with other competition authorities to address issues in global markets. The effect is that potential M&A deals that might previously have been considered impossible to clear can now be revisited, with intelligent and creative planning that has regard to the CMA’s (and the government’s) new strategic priorities in competition policy.

As regards private enforcement of competition law before the courts, 2025 saw a number of important developments in the collective actions regime for competition law infringements, in particular high-value “opt-out” collective claims on behalf of large classes of customers. There was the first liability finding by the Competition Appeal Tribunal (CAT) under this regime that Apple had charged excessive fees relating to sales of apps on the Apple app store that were passed on to consumers (a related class action on behalf of app developers is yet to be determined), which has been estimated to result in damages of up to GBP1.5 billion. In addition, there have been a number of claims settled before the CAT, including a GBP200 million settlement with Mastercard in respect of credit card fees (strongly opposed by the funder of the litigation, which wanted to hold out for a higher amount). The CAT has also rejected a number of collective opt-out claims, including one alleging that a telecoms company had charged excessive prices by pricing above a regulated price cap (Le Patourel v BT) and another (Gutmann v South West Trains) alleging, among other things, that train companies had charged excessive prices by not making certain cheaper fares sufficiently available.  One of the CAT’s reasons for rejecting the latter claim was that competition law is not a general law of consumer protection and “the fact that that a dominant company could have carried out a particular aspect of its business better or in a different way that would have benefited consumers, does not mean that the conduct crosses the line to constitute an abuse.”

Changes in the Way Practitioners Are Advising on the Law

The new areas of law on which UK competition lawyers now advise and the changes to public and private enforcement of competition law have necessitated investments by firms in training for their lawyers and clients, as well as business development and thought leadership initiatives to capture work in these growth areas. Many teams are expanding as a result.

UK law firms are also adapting to the rapid improvements in generative AI technologies, seeking to offer their services more cost-effectively and quickly by finding ways to use AI responsively. For competition lawyers, the initial focus has been on the “low-hanging fruit” of dealing with large volumes of documents that are disclosable to a competition authority or court and increasing the speed of researching legal and factual points, while retaining rigorous quality control and standards. However, the firms that will gain an edge in this rapidly evolving market are those that identify smart and innovative ways to use these new technologies to create advantages for their clients.