2025 was another busy year in the UK competition litigation arena, marked by a succession of significant milestones, trials, and judgments.

In this article, we explore some of the main themes from 2025 and look ahead to 2026, including:

■        Hitting the ten-year mark for the opt-out collective actions regime.

■        The growing jurisprudence on key economic issues.

■        The Competition Appeal Tribunal’s new practice direction on expert evidence.

■        The Department of Business and Trade’s ongoing review of the opt-out collective actions regime.

Ten years of the opt-out collective actions regime

October 2025 marked ten years since the Consumer Rights Act 2015 introduced the opt-out collective actions regime for competition law cases. Figure 1 below illustrates that, over this period, slightly more than 60 such cases were registered with the Competition Appeal Tribunal (‘the Tribunal’), around half of which have now been certified. These cases relate to a range of types of alleged infringing conduct across multiple different sectors, a large proportion of which have been brought on a standalone basis rather than ‘following-on’ from an infringement decision.

Figure 1: Evolution of collective proceedings cases registered with the Tribunal 

Source: Frontier Economics, Tribunal website.
Note: See endnote for details of the cases underlying this figure. 

Figure 1 masks an important trend that has emerged in the collective actions landscape: many claims stem from the same alleged underlying conduct, whether through multiple actions against different defendants, cases brought at different levels of the supply chain, or overlapping claims that have triggered carriage disputes. Taken together, these affect around half of the cases in Figure 1.

Figure 1 also shows that most of the cases have been filed since 2020, following the Supreme Court's judgment in Merricks v Mastercard in which it provided clarification on how the Tribunal should approach certification. The number of new cases registered before the Tribunal has fallen in more recent years relative to earlier periods – for example, almost 20 cases were registered in 2023 and 11 in 2024, whereas four were registered in 2025.

As shown in both Figure 1 and Figure 2 below, few collective actions have reached substantive judgment or settlement (of the 33 collective proceedings that have been certified, only seven have seen an approved settlement or substantive judgment by the Tribunal. These are Le Patourel v BT, Merricks v Mastercard, the three Gutmann v Train Operators cases, Kent v Apple, and McLaren v MOL & Others).

However, activity on this front has increased over the past two years as the frontrunner cases have approached trial and the first substantive judgments have been handed down – including Le Patourel v BT in 2024, followed by Gutmann v Train Operators and Kent v Apple in 2025. This has been complemented by increased settlement activity, including in Merricks v Mastercard and McLaren v MOL & Others in RoRo.

Figure 2: Status of collective proceedings cases registered with the Tribunal

Source: Frontier Economics, Tribunal website.
Note: See endnote for details of the cases underlying this figure. 

Figure 2 also shows the considerable diversity in how collective actions have progressed through the Tribunal. For example:

■        Many cases have yet to reach the certification stage – of the cases registered since the start of the regime, 15 remain at the pre-certification stage. While there is now a significant body of jurisprudence on certification, this will no doubt continue to grow as these additional cases find their way to certification.

■        Certification is not a foregone conclusion – 15 claims were not certified for various reasons, including eight that were refused certification (although this figure includes the six Water cases which were heard together).

All of this suggests that we are still very much in the learning phase of the collective actions regime, with plenty of activity to come in 2026 and beyond. This includes new cases that have recently been announced (for example, Newman v Rightmove, Le Patourel v Apple & Amazon, McLaren v UK Housebuilders, and Daley v Apple), trials scheduled in 2026 for a number of ongoing cases (including Neill v Sony and Coll & Rodger v Google), and substantive judgments in cases which have already reached trial (such as in Consumers’ Association v Qualcomm). Figure 2 may therefore look very different in twelve months’ time.

The growing jurisprudence on key economic issues

In 2025 there were a number of important judgments in both standalone and follow-on cases, which have added to the growing jurisprudence on a number of key economic issues in competition litigation. We expect judgments in 2026 to add to this further.

■        Excessive pricing cases in the spotlight. In 2025 the Tribunal handed down its judgment in Kent v Apple and Le Patourel v BT concluded after the Court of Appeal refused to grant the class representative permission to appeal the Tribunal’s 2024 judgment. Read together, the two cases offer important guidance on how the Tribunal is likely to approach the United Brands test for assessing whether a firm has abused its dominant position through the charging of prices that are considered to be excessive and unfair. For example:

□        both cases suggest that the level of excess identified under Limb 1 of United Brands is likely to be taken into account in the assessment of unfairness under Limb 2. In Kent, the Tribunal considered the level of excess to be ‘useful information’ which fed into its in-the-round assessment of Limb 2; and

□        in both cases the Tribunal emphasised the evaluative nature of the economic value assessment in Limb 2, and that this assessment is necessarily case-specific.

■        Further learnings on the Tribunal’s approach to assessing pass-on. Several judgments handed down by the Tribunal during 2025 considered the issue of pass-on of a potential overcharge – Stellantis v Autoliv, Spottiswoode v Nexans & Others and London Array v Nexans & Others, (one judgment addressing issues common to two separate proceedings) and Kent v Apple. While these rulings underscore that any assessment of pass-on is necessarily case-specific, they also potentially provide guidance on how the Tribunal is likely to approach this assessment. In particular, they suggest that the Tribunal is likely to be cautious about making broad inferences based solely on a single and definitive source of evidence, and that the ‘broad axe’ may play an important role in determining the Tribunal’s findings. Looking forward to 2026, a potential judgment in the Umbrella Interchange cases and the Court of Appeal hearing in Granville v LG Display will give further insight into how courts approach the assessment of pass-on.

■        The value of different economic analyses in the toolbox for assessing overcharge. London Array v Nexans & Others and Stellantis v Autoliv add to the growing number of cases where a UK court has considered detailed economic evidence on overcharge (alongside BritNed v ABB, BT/Royal Mail v DAF and Granville v LG Display). These judgments highlight that:

□        Econometric evidence may not always be the most appropriate method for assessing overcharge. For example, in London Array v Nexans & Others, although it was recognised that econometric approaches can be useful, the economic experts agreed that, given the specific features of the case, an alternative margin comparison approach was to be preferred. This was because the econometric approaches were unable adequately to explain the observed variation in margins across the transactions for which data was available, and did not produce results that were consistent with the factual evidence.

□        The Tribunal will scrutinise the probative value of econometric evidence closely. In Stellantis v Autoliv, the Tribunal assessed detailed econometric evidence submitted by the claimant’s expert and considered that this evidence did not demonstrate the existence of an overcharge. Of particular note in this case is that the Defendants focused on a critique of the econometric evidence put forward by the Claimants’ economic expert, rather than adducing their own evidence on overcharge.

■        Clarifying the limits to the duties of dominant undertakings. Finally, the Tribunal's judgment in Gutmann v Train Operators clarified that the responsibility of dominant firms does not extend to a requirement to ‘promote or advertise a product that will benefit some of its customers so as to increase their awareness of that product’. This is likely to set an important precedent going forwards for the legal test in certain abuse of dominance cases.

New practice direction on expert evidence

2026 will be the first year under the new Practice Direction for expert evidence, which was issued by the Tribunal in December 2025.

As we have previously observed, judgments from the Tribunal in recent years have expressed frustration regarding the volume of expert evidence, the breadth of issues covered by experts and the perception that at times experts have not acted in accordance with their duties to the court. The Practice Direction sets out a number of principles that are relevant to these issues, with an emphasis on expert independence and directing experts to focus on key issues to assist the Tribunal.

On expert independence, the Practice Direction emphasises the importance of an expert’s duty to provide objective and unbiased evidence before the Tribunal. This includes:

■        Disclosure of prior work: the Practice Direction calls for the early disclosure of experts’ prior work for their client or related to the case at hand. It also explains that any failure to do so may result in evidence being disregarded.

■        Economic methodologies: the Practice Direction explains that experts are expected to be able to justify their methodological choices, and to be able to consider how their results and conclusions might change under alternative approaches.

In relation to the experts assisting the Tribunal, the Practice Direction highlights a number of techniques that the Tribunal may use to narrow the scope of the issues addressed by the experts and/or to manage the volume of evidence that they produce. These include:

■        Early engagement between the parties: this may include directing the parties to submit lists of questions to be considered by the experts, or to set out the factual or legal assumptions on which the experts should rely when preparing their evidence. The Practice Direction also indicates that the Tribunal may direct joint expert meetings at any stage of the process. The Tribunal expects experts to have constructive meetings, conceding ground where appropriate, with the objective of narrowing the list of issues in dispute ahead of trial.

■        Approach to disclosure: the Practice Direction explains that experts should keep disclosure requests ‘narrow and targeted’, and that the Tribunal may ask experts to justify their requests.

■        Expert evidence: the Tribunal is ‘likely’ to set page limits for all expert reports. The aim is for ‘concise’ reports which are ‘confined to the issues in dispute between the parties’. Experts should use plain English wherever possible, with technical annexes to cover the detail only if needed.

We expect 2026 to provide further clarity on how the principles set out in the Practice Direction will play out in practice across the broader suite of cases before the Tribunal, both in terms of how the Tribunal will apply them and how experts will respond to the guidance provided in the Practice Direction. For example, it will be interesting to see how the Tribunal will seek to strike the balance between its desire to receive more focused expert evidence, with the risk that this results in expert evidence that does not consider, in sufficient depth, the issues that the Tribunal considers to be most relevant at trial.

DBT review – shaping the next decade?

The Department for Business and Trade’s call for evidence announced in August 2025 on how effectively the opt-out collective actions regime is functioning led to a flurry of responses from law firms, class representatives, and consumer and business associations. Based on the responses that were made publicly available, the call for evidence has triggered lively debates – including around:

■        Whether it is possible to assess meaningfully the functioning of the regime at this point in time, given its relative infancy and the small number of cases reaching resolution.

■        The extent to which the scope of the regime should be expanded beyond competition law to areas such as consumer law, data protection and environmental law, or alternatively restricted to exclude standalone abuse of dominance cases and indirect claims – a debate that is also live in Scotland, where the Scottish Civil Justice Council is considering whether to introduce opt-out group proceedings and, if so, whether they should extend to all civil claims (as with opt-in group proceedings) or only certain areas of litigation.

■        The significant costs and uncertainties inherent in collective proceedings, and whether these can be reduced – for instance through revisiting the threshold for certification or introducing measures that promote earlier and more effective dispute resolution and settlement.

The deadline for responses was mid-October, with the DBT currently reviewing the submissions to consider what, if any, reforms to put forward. It has recently been reported that the DBT will propose changes to the regime and is preparing to consult on these. The Government has already signalled its appetite to intervene, announcing legislation to mitigate the impact of the PACCAR judgment on funders and regulate third-party litigation funding agreements. Any further proposals that emerge over the coming year – and the debates they will inevitably ignite – are likely to play an important part in shaping the next chapter of the opt-out collective actions regime.

Notes on Figure 1 and Figure 2

1. Figure 1 and 2 reflect cases that were listed on the Tribunal website as at 26 January 2026. This excludes cases that have recently been announced but are not yet displayed on the Tribunal website, such as Newman v Rightmove, Le Patourel v Apple & Amazon, McLaren v UK Housebuilders, and Daley v Apple.
2. Substantive judgment refers to a judgment that determines the outcome of the case. It therefore excludes, for example, the judgment on ROC issues in Spottiswoode v Nexans & Others and the judgment on causation and value of commerce in Merricks v Mastercard.
3. Cases that are listed separately on the Tribunal website are counted individually. For example, the five cases that received a substantive judgment in Figure 1 include the three Gutmann v Train Operators cases listed separately on the Tribunal website (one of which is treated as partial settlement/substantive judgment for the purposes of Figure 2), as well as Le Patourel v BT and Kent v Apple; and the eight cases that were refused certification in Figure 2 include the six Water cases listed separately on the Tribunal website.
4. Of the 33 collective proceedings that have been certified, seven have seen an approved settlement or substantive judgment by the Tribunal. These are Le Patourel v BT, Merricks v Mastercard, the three Gutmann v Train Operators cases, Kent v Apple, and McLaren v MOL & Others.
5. Arthur v Alphabet and Pollack v Alphabet are treated as a single case as they were consolidated into Ad Tech Collective Action LLP v Alphabet. Consumers Association v JJB Sports is excluded as it was registered in 2007 under the previous regime.
6. Evans v Barclays is treated as stayed, as the Tribunal declined to certify the claim on an opt-out basis and rather stayed the proceedings to allow for it to potentially be brought on an opt-in basis. The recent Supreme Court judgment upheld the Tribunal’s assessment. O’Higgins v Barclays is treated as withdrawn as, although the Tribunal also stayed the claim to allow for it to potentially be brought on an opt-in basis, O’Higgins v Barclays was subsequently discontinued.
7. Cases are treated as certified at the second attempt in Figure 2 where the Tribunal has issued two judgments on the CPO application. These cases are Merricks v Mastercard, Gormsen v Meta, and the four cases brought by Commercial and Interregional Card Claims I and II Limited against Mastercard and Visa.