UK High Court Rejects Most Dieselgate Claims by 1.6 Million Car Owners
10 reported
A UK high court judgment has rejected most allegations in a "dieselgate" group action claim brought on behalf of 1.6 million UK owners of polluting cars. Lady Justice Cockerill ruled that in the majority of instances, the relevant strategy did not constitute a prohibited defeat device, but found that technology in some Mercedes and Peugeot-Citroën cars could be defeat devices. The case, the largest group action trial in English legal history, was heard over 15 weeks between October 2025 and March 2026, focusing on 20 vehicles from five manufacturers. Claimants' lawyers said they are considering appealing, arguing the judgment creates a significant divergence between Great Britain and much of Europe. Manufacturers including Mercedes, Nissan, Renault, and Stellantis welcomed the ruling, with some considering appeals over the upheld allegations. The verdict comes more than a decade after Volkswagen's diesel emissions cheating was first discovered.
What’s reported
Lady Justice Cockerill found that in most instances, the relevant strategy did not constitute a prohibited defeat device.
The judge found that technology in some Mercedes and Peugeot-Citroën cars could constitute defeat devices.
The case was the largest group action trial in English legal history, heard over 15 weeks from October 2025 to March 2026.
The trial focused on 20 vehicles sold by Mercedes, Ford, Renault, Nissan, and Peugeot/Citroën from 2009.
Claimants' lawyers are considering an appeal, citing a divergence between Great Britain and EU law.
Mercedes-Benz said the court ruled "very largely in favour" of the manufacturer but is considering an appeal over the non-compliant vehicle.
Stellantis (Peugeot-Citroën) said it is considering an appeal over the upheld allegations.
Nissan stated its technologies did not constitute defeat devices; Renault said its cars were built in accordance with regulations.
The case was brought by more than 20 law firms, led by Leigh Day and Pogust Goodhead.
Campaign group Mums for Lungs called the ruling a "setback" but said the scientific consensus on diesel car toxicity remains.
Key figures
Lady Justice Cockerill (high court judge)
Martyn Day (senior partner, Leigh Day)
Anna Varga (Pogust Goodhead)
Jemima Hartshorn (director, Mums for Lungs)
Sources: The Guardian
