Drivers across Britain could be in line for payouts worth thousands of pounds as a major “dieselgate” court case opens in London on Monday, potentially costing carmakers billions.
About 1.6 million motorists have joined the class action lawsuit against 14 leading car manufacturers accused of fitting “defeat devices” to cheat emissions tests. The High Court case, led by law firm Leigh Day, alleges that between 2010 and 2020, the carmakers manipulated testing systems to make diesel vehicles appear less polluting than they actually were.
The landmark trial described as Britain’s biggest class action will initially focus on 20 vehicle models produced by Mercedes-Benz, Ford, Nissan, Renault, and Peugeot Citroën, owned by Stellantis. Engineers and software experts will examine technical data to determine whether the devices were used to falsify emissions results, and whether the manufacturers intentionally breached regulations.
Leigh Day’s co-founder Martyn Day said:
“The claims are worth a few thousand pounds each. The amount at stake is billions and billions of pounds. It’s a massively big deal for an industry already under strain.”
The Department for Transport (DfT) is investigating several top-selling car brands to determine the extent of defeat device use. The extra emissions linked to the devices are estimated to have contributed to 124,000 premature deaths from air pollution across the UK and EU between 2009 and 2024.
A judgment is expected next summer, with compensation decisions likely in October 2026.
All five leading defendants have denied wrongdoing.
- Mercedes-Benz said the claims were “without merit”.
- Renault stated that its vehicles “met all regulatory standards”.
- Nissan insisted it was “fully compliant” and supportive of tougher emissions testing.
- Stellantis said it would “strongly defend against unfounded claims”.
- Ford declined to comment.
If successful, the case could surpass Volkswagen’s 2022 settlement of £193 million, marking the largest consumer compensation case in British legal history.
