Executive Summary
- What’s new: While collective proceedings for competition-related damages remain the most popular means to seek collective redress, increasingly, mass claims are being pressed through group litigation orders (GLOs) and joint claims in the High Court.
- Why it matters: Cases brought under GLOs or as joint claims do not enjoy the safeguards for either claimants or defendants that are provided under the Competition Appeal Tribunal’s procedures, and there is little or no regulation of funders supporting GLO actions. As a result, defendants increasingly face exposure to vast damages claims.
- What to do next: Defendants will need to develop new strategies to address the risk of novel collective actions, and monitor any changes to rules for these cases, as well as possible moves by the UK government to regulate litigation funders.
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The Current State of Class Actions in the UK
The UK has witnessed a dramatic transformation in its collective redress landscape over the past decade. Traditionally cautious about adopting the US-style class action model, the UK has nonetheless seen a surge in mass claims, particularly since the introduction of the opt-out regime for competition law infringements in 2015 and the Supreme Court decision in Merricks. The Competition Appeal Tribunal (CAT) has become one of the busiest courts in the country, with a rapidly growing docket of collective proceedings. Over 20 collective actions have been certified, with many more awaiting certification, and the total value of claims exceeded £160 billion by the beginning of 2025, according to a report in The Times.
While the CAT regime is limited to competition law infringements, the possibility for mass claims has been enabled through GLOs and joint claims in the High Court. These mechanisms, though procedurally distinct from the CAT’s collective proceedings, have permitted large-scale claims in areas such as environmental harm, securities fraud and data breaches. The result is a UK class action environment that is active and growing but marked by significant uncertainty, with claimants, funders and law firms pushing the unsettled boundaries of what is possible.
Group Litigation: Class Actions by the Back Door?
With the CAT regime restricted to competition law issues, claimants are using GLOs and joint claims to pursue mass redress in other areas. These “backdoor” class actions often attract funders due to the potential for large aggregate damages, even where individual recoveries are modest. The economics of funding — where funders’ returns can sometimes dwarf damages distributed to class members — has become a flashpoint, as seen in the public dispute over the Merricks v Mastercard settlement.
Although the CAT’s collective proceedings regime is the only formal “opt-out” class action mechanism in the UK, group litigation is thriving through alternative routes — without the same procedural safeguards. The largest and most high-profile mass claims in the UK are not competition cases, but group litigation in the High Court. Sixteen GLOs were issued in the High Court between 2001 and 2024, and 125 in all since 2001. The “dieselgate” emissions litigation against car manufacturers, for example, involves thousands of claimants and claims valued in the billions. Similarly, the Município de Mariana v BHP Group Ltd. case, arising from the Fundão dam collapse in Brazil, has seen over 732,000 claimants seeking more than £36 billion in damages. Other cases in recent years involve public nuisance claims against meat processing, steel and composting facilities, and damages claims stemming from an oil spill and the use of intrauterine device contraceptives.
These GLOs and joint claims are, in effect, class actions “by the back door.” The danger is, the GLO procedure lacks the collective proceedings regime’s key protections against abuse such as the initial certification requirements, suitability assessments for class representatives and judicial scrutiny of funding arrangements. The result is a system where mass claims can proceed with less oversight, raising concerns about unmeritorious or speculative claims, inconsistent outcomes and the potential for disproportionate costs and burdens on defendants.
Is the UK Regime More Risky for Defendants Than the US?
The UK’s evolving group litigation landscape presents unique challenges for defendants — arguably more so than in the US in certain respects. In the US class action system, there are procedural “guardrails” that protect defendants, such as early motions to dismiss and strict class certification standards. In contrast, the UK’s GLO and opt-out regimes, especially when combined with third-party litigation funding, can expose defendants to massive, complex and expensive claims with less scope for early dismissal opportunities.
The Role of Funders
Funders play a pivotal role on both sides of the Atlantic, but their influence in the UK is particularly pronounced. The UK is now the world’s second-largest litigation funding market, with funders bankrolling the majority of large group claims. Their economic model — seeking a return on investment from damages recovered — drives the pursuit of high-value, high-profile cases. However, issues regarding the degree of regulation in the UK funding sector has sparked debate, with critics of regulation warning of risks to both defendants and class members. The government is now reviewing whether the regime incentivizes speculative claims.
Where Are Claimants Going Next?
Claimants and their lawyers are increasingly creative, seeking to expand the scope of class actions beyond competition law. Environmental claims, securities fraud, data privacy and even “greenwashing” allegations are all fertile ground. The recent attempt to bring environmental class actions against water companies in the CAT, though ultimately dismissed on statutory grounds, signals a willingness to test the boundaries of collective redress.
Defendants’ Playbook
Defendants are responding with a range of strategies: challenging the suitability of class representatives, contesting funding arrangements, seeking to limit the scope of claims and pushing for early resolution or dismissal where possible. The CAT’s recent willingness to refuse certification on suitability grounds (as in Riefa v Apple and Amazon) may embolden defendants to test these issues more aggressively.
Government Review: A Tipping Point?
The UK government is now reviewing the litigation funding regime, prompted by concerns that the current system may incentivize speculative or unmeritorious claims. The Civil Justice Council has recommended legislative reform to clarify the status of funding agreements and introduce greater oversight. The outcome of this review could reshape the economics and risk profile of group litigation in the UK for years to come.
Conclusion
The UK’s group litigation landscape is at a crossroads. As claimants, funders and law firms continue to innovate and expand the scope of mass claims, the line between formal class actions and “backdoor” group litigation is increasingly blurred. For defendants, the risks are real and growing — demanding new strategies and a close watch on regulatory developments. The next phase of reform will determine whether the UK can balance access to justice with the need to protect against abuse and ensure fair outcomes for all parties.
Professional support lawyer Elizabeth Malik contributed to this article.
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