Most Members will by now be aware of the High Court ruling on 10th of July this year in the Pan-NOx Diesel Emissions Group case (Various Claims v Mercedes-Benz Group and Others). The case was the largest group action in English legal history, with around 1.6 million owners of Euro 5 and Euro 6 diesels alleging that manufacturers fitted “prohibited defeat devices” that turned down the emissions controls once a vehicle was off the test rig and on the road, pushing up nitrogen oxides (NOx) in normal use. The first trial ran from October 2025 into the spring and examined sample vehicles from five lead defendants: Mercedes, Ford, Renault, Nissan, and Peugeot-Citroën. In a 369-page judgment Lady Justice Cockerill, rejected most of the principal allegations. Her central ruling was that the vast majority of the engine calibrations and emissions-control strategies examined at trial did not constitute unlawful and “prohibited defeat devices”. She found that the definition of “defeat device” is not simply any calibration that behaves differently on the road; it is a device that senses it is being tested and operates with the purpose of making the emissions system work better under test than in ordinary driving. Intention, in other words, is the hinge and, on that narrow reading, the majority of the allegations failed. MILS Head of Legal, Christopher Baylis (Barrister), has been heavily involved throughout the litigation. Whilst we welcome the decision, we would advise members to remain cautious for three main reasons: First, the case is a staging post, not a finish line. This was a liability trial on sample cars and lead defendants only. A further trial is listed in October this year to deal with remedies and damages, appeals look close to certain from both sides, and the claims against the remaining manufacturer groups, including Volkswagen, Jaguar Land Rover, BMW, Vauxhall, Toyota and others, have yet to be heard. In other words, this case is far from over. Second, and relatedly, to reach her narrow definition of a defeat device, the judge declined to follow several post-Brexit decisions of the Court of Justice of the European Union. That was a legitimate exercise of the freedom our Courts now exercise over retained EU law, but it leaves the UK, for the moment, as an outlier that has taken a more permissive view than the rest of Europe regarding what constitutes a defeat device. That sort of gap is precisely the ground upon which the claimants say they will appeal, and it’s not an overly comfortable position. Certainly, we would not treat the ruling as a license to market older diesels as “cleared” or “fully compliant” at present. Finally, the judge held that the emissions rules do give consumers a private legal right to sue. The claimants (mostly) lost on whether particular devices were unlawful, not on whether they could bring a claim at all. A group action against a manufacturer is a different beast from a buyer’s direct claim against the dealer who sold the car, under the Consumer Rights Act 2015 or for misrepresentation. This ruling leaves those direct routes untouched, and it is quite likely that, in the wake of this decision, consumers will test such claims. It is also worth noting that, whilst the ruling effectively crushes the possibility of widespread payouts for the great majority of the 1.6 million claimants, there remains a relatively small number of affected Mercedes-Benz and Peugeot-Citroen owners who may still pursue compensation for “defeat devices”. So, the practical steer is a familiar one. Enjoy the reduced pressure, but keep your descriptions of diesel stock accurate and modest, preserve any manufacturer recall or software-update paperwork, and keep half an eye on October and on the appeals. As always, this advice is general in nature and should be tailored to the circumstances of any individual case. As an RMI member, you have access to the RMI legal advice line, as well as a range of industry experts who can assist you. If you find yourself facing any of the issues outlined above, please contact us at any stage for advice and support as appropriate. Motor Industry Legal Services Motor Industry Legal Services provides fully comprehensive legal advice and representation to UK motor retailers for one annual fee. It is the only regulated law firm in the UK which specialises in motor law and motor trade law. MILS currently advises over 1,000 individual businesses within the sector as well as the Retail Motor Industry Federation (RMI) and its members.