UK: A Competition Law: Litigation Overview

Private Enforcement Takes Centre Stage

Competition litigation in the UK continues to spawn high-stakes claims brought both on an individual and a collective basis for amounts running into the billions. That litigation is increasingly brought before or alongside investigations by competition authorities. The result is that competition enforcement in the UK is in some instances moving from authorities to claimants, with those authorities monitoring private actions, taking a “watch and wait” approach, or intervening in private litigation, rather than initiating their own investigations.

B2B litigation has long been a feature of the competition litigation landscape and in the last year there have been significant judgments on issues of causation, pass-on and abuse of dominance. The High Court and the Competition Appeal Tribunal (the “Tribunal”) continue to scrutinise what the claimant business would have done in the counterfactual – ie, would it have traded profitably (Cabo) and would it have won additional business (Global-365). The Court of Appeal has also weighed in on core competition law issues, as seen in Deckers on vertical infringements. As litigants continue to rely on private enforcement, the courts are at the forefront of shaping the parameters of competition law.

Collective Actions Face a Tougher Tribunal

Over the last decade, collective actions, buoyed by an active third-party litigation funding market, have been at the heart of antitrust litigation in the UK. These claims account for significant court resources and give rise to difficult policy and legislative debates. While engaging the same core substantive legal issues as single-party litigation, collective actions are distinct by virtue of their scale, the involvement (in many cases) of consumers, and the resulting complexity of case management. In addition, many recent collective actions have been brought at the fringes of competition law, drawing significant judicial and market commentary.

Over the course of 2025, the Tribunal’s approach to certification has shifted, resulting in:

• more cases being refused certification;
• certification on an opt-out basis becoming more difficult;
• class representatives coming under increased scrutiny; and
• cost/benefit analysis being at the forefront of the Tribunal’s considerations.

In 2025, the Tribunal refused to certify three cases: Rowntree, Roberts and Riefa. In Rowntree, the claim was struck out, inter alia, because the proposed class members could not show a legal entitlement to the royalties that were in question. In Riefa, the proposed class representative was not authorised as she failed to have sufficient understanding of the relevant funding arrangements. In Roberts, a statutory exception meant compensation was a matter for Ofwat to determine.

Closer scrutiny at the certification stage is likely to persist in light of the Supreme Court’s judgment in Evans. Evans makes clear, contrary to previous authority, that the strength of the claim is an important factor at certification. Opt-out proceedings must be justified and, in some cases, this may make certification harder. It may also result in “hybrid” cases with split classes – large commercial entities forming opt-in classes and smaller entities or consumers making up opt-out classes.

Class representatives have come under increased scrutiny, with the Tribunal suggesting on more than one occasion that they should satisfy additional requirements in order to secure certification. These additional requirements, while not formal conditions for certification, are becoming commonplace. They include the need for a consultative panel, more formalised proposals for consulting with the class, ensuring class representatives obtain specialist and independent advice on any litigation funding, and having to explain the genesis of the claim. Questions have also been raised in recent judgments as to appropriate levels of class representative remuneration, in the context of the overall scrutiny of the costs of bringing collective proceedings.

The assessment of the costs of bringing collective proceedings as compared with the likely return to the class (if successful) has also gained prominence. In the early collective cases, cost/benefit analysis arguments did not gain much traction with the Tribunal. Following mixed levels of success by claimants, high costs of proceedings and low consumer take-up, cost/benefit analysis has become a key consideration. In the Salmon judgment, the Tribunal had significant concerns around the cost/benefit analysis, which led the Tribunal to decline certification at that stage.

Recent certification trends reflect an evolution in the Tribunal’s approach to collective actions over the first ten years of the regime as cases progress and experience is gathered. The Tribunal is focused on ensuring that claims are brought and pursued for the benefit of class members and the public interest, priorities that are also seen in the Tribunal’s scrutiny of distribution plans to ensure the best possible chance of funds making their way to the class. These shifts cumulatively suggest that the Tribunal will continue to demand more of class representatives than it did at the beginning of the regime.

We also now have a developing body of case law indicating how the Tribunal will approach the competition issues raised in these claims at trial, with mixed success for class representatives and defendants. The Tribunal has rejected more novel theories of harm, such as in the Boundary Fares litigation. In that case, the Tribunal dismissed the claim, on the basis that the class representative’s evidence could not support the allegations that the defendants had abused their dominant position. The Tribunal held that the class representative could not resort to theoretical speculation about how business practices might cause harm, concluding that “competition law is not a general law of consumer protection”.

Case Management, Expert Evidence and Upcoming Policy Developments

At a time when the Tribunal’s caseload is increasingly dominated by complex, high-value collective actions that turn on expert evidence, the Tribunal has introduced a new expert practice direction, which is having a significant impact on how economic and technical expertise is managed. The practice direction seeks to address two perceived problems:

• the proliferation of expert reports and sheer volume of expert evidence; and
• apparent expert partiality and advocacy on the part of experts.

In addition to case management developments driven by the Tribunal, the government is considering broader policy and legislative changes. At the time of writing, there are three policy developments on which the market awaits updates:

• the Department for Business and Trade’s review of the UK’s opt-out collective action regime, which could reshape the approach to opt-out proceedings;
• the introduction of legislation to reverse the Supreme Court’s PACCAR decision on funding; and
• the Law Commission’s assessment of the benefits and risks of a collective regime for consumer law claims.

In circumstances where the Tribunal has clearly indicated that consumer protection cases should not be shoehorned into the competition collective actions regime, the introduction of an opt-out class action regime for consumer claims would be a significant step that could make England and Wales a leading venue for a wider range of claims, leveraging the existing active claimant bar and funding market, with significant impacts for businesses.