Diesel emissions claims are among the largest pieces of mass litigation ever run through the courts of England and Wales. They do not fit the popular image of a mass disaster lawsuit. There is no single explosion, no single date, no single site. Instead there are hundreds of thousands of individual claims, each worth a few hundred or a few thousand pounds, gathered together so they can be argued once rather than one at a time. That gathering is what makes the cases commercially possible, and it is also why the funding model, usually described to the public as “no win, no fee”, deserves a closer look than the advertising gives it.
This article walks through the machinery: how claims are grouped, what a no win, no fee agreement actually commits a claimant to, who covers the costs while a case is running, and how a settlement is divided if one is reached. Diesel emissions is the worked example, but the same structure sits under many other large group claims.
What counts as a group claim
In England and Wales, the main tool for managing many similar claims is the Group Litigation Order, or GLO. A GLO does not merge claims into a single lawsuit with a single claimant. Each person keeps their own case, but the court manages the shared questions together under Civil Procedure Rule 19 and Practice Direction 19B. A GLO must identify the common issues of fact or law, set up a group register, and appoint a management court. Claimants join by opting in: they issue a claim and are entered on the register. The court usually sets a cut-off date, after which new claimants need permission to join.
GLOs are not common. More than 120 have been made since the regime began in 2000, according to figures compiled by the law firm Mishcon de Reya in 2024. The scale is deliberate. A GLO is meant for claims that would be uneconomic to run individually but share enough common ground to justify one coordinated effort.
There is a second route that matters for consumer claims. For competition law disputes, the Competition Appeal Tribunal can certify “collective proceedings” under the Consumer Rights Act 2015, either opt-in or opt-out. Opt-out means people in a defined class are included unless they actively leave. Settlements in opt-out cases require approval by the Tribunal, which assesses whether the terms are just and reasonable.
| Feature | Group Litigation Order (GLO) | Collective Proceedings Order (CPO) |
|---|---|---|
| Where it is used | High Court, King’s Bench, Chancery or County Court | Competition Appeal Tribunal, for competition law claims |
| How claimants join | Opt-in: each claimant is entered on the group register | Opt-in or opt-out, depending on certification |
| Who steers it | A lead solicitor, often with a steering committee of claimant firms | A class representative, supported by its legal team |
| Key gatekeeping step | The court makes the GLO and defines the shared issues | The Tribunal certifies the class and the claims as suitable |
| Settlement | Terms agreed between the parties | Opt-out settlements require Tribunal approval |
Sources: Civil Procedure Rules Part 19 and Practice Direction 19B; published summaries of the regime by Ashurst and Osborne Clarke, 2024.
Diesel emissions claims have run mainly through the GLO route in the High Court, which is why they behave like an opt-in mass claim rather than a US-style class action.
The legal trigger: what makes an emissions claim possible
The claims rest on a specific prohibition. Under Regulation (EC) No 715/2007, a “defeat device” is any element of design that senses parameters such as temperature, vehicle speed or engine speed and reduces the effectiveness of the emission control system under conditions expected in normal driving. Article 5 of the regulation prohibits their use, subject to narrow exceptions. The regulation sets the definition and the exemptions; national courts and the Court of Justice of the European Union have interpreted how far those exceptions reach.
Two strands of interpretation matter. In December 2020, the Court of Justice ruled in case C-693/18 that protecting an engine from clogging or ageing is not, by itself, a valid justification for a defeat device. In July 2022, further rulings held that a device operating for most of the year under normal conditions is not permissible, and that the narrow exception applies only where no other technical solution is possible. Those judgments did not decide the UK claims, but they shaped how the law is now understood.
The health context explains the scale of the litigation. A May 2025 assessment by the Centre for Research on Energy and Clean Air estimated that excess nitrogen oxide emissions from Euro 5 and early Euro 6 diesel vehicles across the EU and UK were linked to around 205,000 premature deaths over the period 2009 to 2040, with roughly 124,000 of those attributed to 2009 to 2024. Different studies use different methods and produce different totals, so these figures are best read as estimates rather than a fixed count. What the research consistently points to is that real-world nitrogen oxide emissions from many diesel vehicles were higher than laboratory tests suggested.
Manufacturers have disputed the claims, and courts decide each case on its evidence. The point for this article is procedural: the shared questions of law and fact are exactly what a group claim is designed to resolve once for everyone.
“No win, no fee” is a description, not a legal term
There is no legal instrument called a no win, no fee agreement. It is a consumer-facing label covering at least two different contracts, and the Solicitors Regulation Authority is explicit that the phrase can obscure as much as it explains.
A conditional fee agreement, or CFA, is a deal between client and solicitor in which the solicitor’s fees are payable only if the case succeeds, usually with an extra success fee on top. A damages-based agreement, or DBA, works differently: if defined success criteria are met, the solicitor takes an agreed percentage of the money recovered, regardless of how many hours went into the case.
Both can sit alongside After the Event (ATE) insurance, taken out after the dispute arises to cover the risk of paying the other side’s costs if the claim fails. That distinction matters. The “no win” part normally refers to the claimant’s own lawyer’s fees. It does not, on its own, protect a claimant from an adverse costs order, which is precisely what the ATE policy exists to address. The SRA publishes consumer guidance on no win, no fee agreements that sets out these layers in plain language.
| Feature | Conditional Fee Agreement (CFA) | Damages-Based Agreement (DBA) |
|---|---|---|
| When the client pays | Only if the case succeeds and the agreed criteria are met | Only if the defined success criteria are met |
| What the fee is based on | Normal fees plus a success fee, set at the outset | A percentage of the sums recovered |
| Statutory limits | Success fee capped at up to 100% of normal fees in commercial cases; personal injury rules differ | Up to 25% for personal injury, 50% for most other civil claims, 35% for employment claims |
| Common use | Personal injury and general civil litigation | Consumer group claims and commercial disputes |
Sources: the Damages-Based Agreements Regulations 2013; Pinsent Masons guide to conditional fee and damages-based agreements, 2023.
Who pays to keep a group claim alive
Group claims are expensive long before they produce anything. Court fees, expert reports, disclosure and counsel’s fees arrive early; any recovery arrives years later, if at all. That timing gap is why funding sits at the centre of modern mass litigation. Third party funders may cover some or all of the costs in exchange for an agreed return out of any recovery, usually expressed as a share of damages, a multiple of the amount invested, or the higher of the two.
The funding market itself was reshaped by the Supreme Court’s 2023 decision in PACCAR, which held that a litigation funding agreement giving the funder a return calculated by reference to damages is a damages-based agreement. Because DBAs are unenforceable in opt-out collective proceedings, many funders restructured their agreements around multiples of the amount invested instead of percentages of recovery.
The same timing gap means the financial position of the firms running the claims can affect how long a case can be sustained through the years it may take. Trade coverage such as a report on law firm financial accounts examines how those balance sheets evolve as large group claims progress through the courts.
Where the settlement money goes
When a group claim settles or succeeds, money typically moves in a defined order. The recovery usually arrives as a central sum paid to the claimants’ solicitors, who then distribute it. From that pot come the agreed success fee or DBA percentage, any funder’s return, the ATE premium where it is payable on success, and each claimant’s share of “common costs” such as resolving the shared issues. What remains is divided among group members, normally using a formula set out in the agreement or approved by the court.
The largest UK diesel settlement to date shows how headline and net figures diverge. In May 2022, Volkswagen Group agreed an out-of-court settlement of £193 million with around 91,000 claimants in England and Wales, alongside a separate contribution towards legal costs and other fees. It made no admission of liability. The core sum works out at an average of roughly £2,100 per claimant before any deductions agreed with their representatives. Advertising at the time sometimes suggested payouts equivalent to a large share of a vehicle’s value, while the actual average was well below that. The gap between the two reflects the difference between a headline maximum and what a negotiated global settlement produces across a mixed pool of new and second-hand vehicles.
What claimants are entitled to be told first
The regulator’s expectations are straightforward, even if practice varies. SRA guidance says a provider must explain, before a client signs, what the fee will be if the claim succeeds, what disbursements may be repayable, and how the other side’s costs will be met if the claim fails. It also notes that most agreements carry a cooling-off period, usually 14 days, and that cancelling after it, or leaving a claim partway through, can trigger charges for work already done.
For group claims, the practical questions a claimant should be able to answer in writing are these: what percentage is deducted on success; whether that includes VAT and counsel’s fees; who the ATE insurer is and what the policy excludes; and what happens to the claim if the funder withdraws. Those are mechanical details rather than matters of suspicion, and any provider should be willing to put them in writing before a client commits.
Realistic timelines and hard deadlines
Group claims run on court timetables, not on advertising schedules. A GLO can take years from the first claim to a resolution, and interim steps such as a test case or a funding challenge can add further delay. Limitation periods, the legal time limits for bringing a claim, add another layer: they can differ between claimants and between causes of action, and missing one can end a claim entirely.
Deadlines matter more than many participants expect. In the diesel litigation, the High Court set formal cut-off dates for new claimants in England and Wales across a series of hearings between December 2023 and March 2024, and the final deadline passed in December 2024. Some manufacturers’ claims have closed to new participants; others have not. Anyone wondering about eligibility should check the current position rather than rely on a general guide, because the answer depends on the manufacturer, the vehicle, and the jurisdiction where it was bought or leased.
It is also worth stating plainly what a group claim cannot promise. There is no guaranteed outcome, no guaranteed timeline, and no guarantee that a settlement will match the most optimistic figure in an advertisement. What the structure does offer is a way to pursue a claim that would otherwise be too small to bring alone.
Frequently asked questions
Is a no win, no fee group claim genuinely free to join?
Usually there is no upfront cost to join, and if the claim fails a claimant typically does not pay their own solicitor’s basic fees. However, liability for disbursements, the ATE premium, or part of the other side’s costs can still arise depending on the agreement and the insurance in place. “No fee” is not the same as “no risk”.
Who decides which law firm leads a group claim?
In a GLO, the court appoints a lead solicitor, and claimant firms often form a steering committee. The court may give directions on how that committee operates. Individuals do not normally choose the lead firm; they choose whether to instruct one of the firms involved.
Can I still join a diesel emissions claim?
It depends on the manufacturer and where the vehicle was bought or leased. Many England and Wales claims had cut-off dates in 2024, while some remain open, and claims in Scotland and Northern Ireland follow different arrangements. Check the current position with a regulated firm.
How is the money split when a claim settles?
The recovery is paid into a central sum, agreed deductions are taken, and the remainder is distributed using an agreed formula. In a GLO, costs are commonly separated into individual costs and common costs.
How long does a group claim take?
Anywhere from a couple of years to considerably longer. A settlement reached early can conclude quickly, while a contested case that goes to trial and appeal can run for years. Timelines are not guaranteed.
What percentage of a settlement goes to fees?
It varies. Under a DBA, statutory caps are 25% for personal injury, 50% for most other civil claims, and 35% for employment claims, and those figures do not necessarily include VAT or every disbursement. Under a CFA, a success fee is charged on top of normal fees and is a matter of agreement. The exact figure should be set out before signing.
How this article was put together
This piece explains the general mechanics of group litigation and no win, no fee funding in England and Wales rather than the merits of any particular case. It draws on the Civil Procedure Rules and Practice Direction 19B, Regulation (EC) No 715/2007, judgments of the Court of Justice of the European Union, the Supreme Court’s 2023 decision in PACCAR, guidance published by the Solicitors Regulation Authority, and reporting on the 2022 UK diesel settlement. All sources were checked in September 2026. Figures such as average settlement values are specific to that settlement and are not predictions for other claims. Funding rules and deadlines change, so check the current position before relying on any detail here.