UK High Court Delivers Mixed Ruling in Landmark Diesel Emissions Lawsuit

6 million British car owners. Lady Justice Cockerill ruled that most of the challenged engine software did not qualify as illegal “defeat devices”, technology designed to cheat emissions tests. The decision marks the first UK verdict in the sprawling dieselgate saga, more than a decade after Volkswagen’s cheating was first exposed.

However, the ruling wasn’t a clean sweep for the industry. The judge found that certain technologies used in some Mercedes and Peugeot-Citroën vehicles could indeed be considered defeat devices. Claimants’ lawyers are now weighing an appeal, arguing the decision creates a legal gap between Britain and much of Europe, where similar tactics have been deemed unlawful.

The case, the largest group action trial in English history, spanned 15 weeks and examined 20 vehicle models from Mercedes. Ford, Renault, Nissan, and Peugeot-Citroën.

Automakers welcomed the verdict. Mercedes-Benz said the court ruled “very largely in favour” of the company, though it is considering an appeal on the non-compliant vehicles. Nissan and Renault maintained their technologies were lawful, while Stellantis, owner of Peugeot-Citroën, said it may appeal the upheld allegations.

Campaign group Mums for Lungs called the outcome a setback, but added that the scientific consensus remains clear: these diesel cars are toxic. The fight, it seems, is far from over.