The UK government has launched a review into the opt-out collective actions regime for antitrust law claims. This review comes a decade after the regime’s launch. During this period, the regime has developed significantly, with many claims being issued (now more than 60) and certified amidst much legal wrangling on procedural points. However, despite the proliferation of claims (and a small number of settlements), we have not yet seen the widespread consumer redress that the regime was created to achieve.
On 6 August 2025, the government issued a call for evidence in which it asked 31 questions covering access and funding; scope and certification of classes; alternative dispute resolution (ADR), settlement and damages; and distribution of funds. The deadline for responses is 14 October 2025. Following review of the responses received, the government stated its intention to publish proposals for change to the opt-out collective actions regime, which will be subject to consultation. The sentiment behind the consultation appears to be that certain elements of the regime do not appear to be working as expected, and that adjustments will increase its efficiency and enhance the prospects of damages flowing to consumers.
The opt-out class action regime in antitrust cases
The opt-out class action regime for antitrust cases was introduced by the Consumer Rights Act 2015 with the stated purpose of making it easier for consumers to obtain compensation for loss suffered as a result of a breach of antitrust law. It does not apply to breaches of other areas of law (such as consumer protection and data privacy rules).
It introduced a US-style system by which a suitable class representative could claim against a party that had infringed UK antitrust law on behalf of a class of persons (who may be individuals or businesses) that have been affected by the same anti-competitive conduct. Claims are for an aggregate award, and damages can be brought on a follow-on basis (i.e. relying on an infringement finding by a competition authority) or on a stand-alone basis (i.e. where the burden is on the class representative to prove infringement of antitrust law) and – in relation to the proposed class – on an opt-out or opt-in basis subject to certification.
How has the regime developed?
The first two claims that were issued under the regime (in 2016) fell at the first hurdle (the certification stage). This led to the regime stalling until 2020, when the UK Supreme Court issued a judgment in Mastercard v. Merricks[1] which set the threshold for certification – lower than applied by the Competition Appeal Tribunal (CAT) in the first instance. The first collective proceedings order was made the following year,[2] opening the floodgates for more claims, which have shown no sign of slowing down. Even where claims have failed at the certification stage, the CAT has in many cases been willing to give the claimants the opportunity to reformulate their applications and reapply rather than striking out the claim.
Eight years after the regime was launched, the first settlement was reached and approved by the CAT (in December 2023) in claims brought in respect of a maritime car shipping cartel. This was followed by settlements by other defendants in the same proceedings and – more controversially – by a settlement in the Merricks claim for a reported £200 million (originally quantified at a significantly higher level of £14 billion) which was approved by the CAT in May 2025 despite an intervention from the claim funder, which was disappointed by the low level of the settlement and is currently seeking to judicially review the CAT’s approach.[3]
Nine years following launch of the regime, in late 2024, the first claim proceeded to trial and final judgment.[4] The CAT dismissed the claim, which alleged that BT’s pricing for unbundled voice landlines was excessive, in its entirely. The Court of Appeal subsequently refused permission to appeal which put an end to this claim.
This means that 10 years after launch of the regime, we have seen a limited number of settlements measured cumulatively in the low hundreds of millions of pounds against the backdrop of claims being issued, with a reported value of more than one hundred billion pounds and significant cost to business both in terms of business disruption and legal fees (which the government quantifies in the hundreds of millions but could well exceed a billion pounds sterling).
Why has the government launched a review of the regime?
The stated purpose of the review is to assess ‘the efficacy of the regime – primarily, whether it is delivering access to justice for consumers in a way that brings value without being disproportionately burdensome on business’.
The government acknowledges that the caseload has grown but that only one case has reached trial, which means that there is limited precedent on key issues such as damages and distribution. In this context, the timing of the review might be questioned given the small sample size and the fact that the regime is still evolving.
The call for evidence states that the ‘type of case being brought before the CAT has also developed in unexpected ways’. When the regime was established, the government’s expectation was that the majority of cases would be follow-on (i.e. based on an existing infringement finding). However, the regime has not developed as the government expected, with around 90% of claims being stand-alone, and the majority have been abuse of dominance cases targeting single-firm business practices. Stand-alone claims are materially more burdensome to prove and defend, often involving wide-ranging disclosure to seek to identify and prove an antitrust law infringement. In some cases, collective actions have been issued alleging unconventional breaches of antitrust law – with claimants seeking to frame conduct as an antitrust breach in order to take advantage of the opt-out class action regime which is the only one of its kind in the UK. Examples include claims that would appear, more naturally, to be actionable as breaches of data privacy and consumer rights.
What to expect
The outcome of the review is difficult to predict but a ‘no need for change’ outcome is unlikely. The government will no doubt receive responses from a range of stakeholders with differing incentives and views – ranging from large corporates seeking to restrain the regime (e.g. through tightening the rules that apply to certification) to the claimant bar and funders looking for the government to widen the regime to allow opt-out class actions to be brought in cases that go beyond antitrust law.
It should be encouraging to defendant interests that the review includes scrutiny of the funding industry. The first section of the call for evidence relates to the role played by funders in the regime and explores other ways in which these claims could be funded (including potentially through an Access to Justice fund), and a possible outcome of the review might be a change in funding models. This, in turn, could bring scope to reduce the availability of funding to less meritorious claims.
The review signals the next stage in the evolution of the UK’s collective actions regime. But, meanwhile, the tide of collective actions shows no sign of abating with the claims continuing to progress through the legal process at significant cost to business and the funding industry.
[1] Mastercard Incorporated and Others (Appellants) v. Walter Hugh Merricks CBE (Respondent) [2020] UKSC 51.
[2] Justin Le Patourel v. BT Group plc [2021] CAT 30.
[3] [2025] CAT 28.
[4] Justin Le Patourel v. BT Group plc [2024] CAT 76.
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