The UK is currently witnessing its largest group action trial in history concerning allegations against car manufacturers for installing software designed to cheat emissions tests. Over a decade after the initial “dieselgate” scandal emerged, legal representatives for 1.6 million diesel vehicle owners claim that manufacturers such as Mercedes, Ford, Renault, Nissan, and Peugeot/Citroën implemented “prohibited defeat devices.” These devices allegedly recognized when vehicles were undergoing emissions testing, enabling them to restrict harmful nitrogen oxide (NOx) emissions during these tests.
If the claims are validated, damages could reach over £6 billion. The trial, which commenced recently at London’s high court, will examine vehicles sold since 2009 and contend that actual emissions levels on the road were notably higher than those recorded during testing. The outcome may bear implications for additional manufacturers, as it could set a legal precedent affecting companies like Jaguar Land Rover and Volkswagen, whose cases are currently not part of this trial to streamline proceedings.
The claimants assert that manufacturers prioritized “customer convenience” over environmental compliance, potentially contributing to significant health issues related to pollution. A report cited by the claimants indicated that excess NOx emissions have led to 124,000 premature deaths across the UK and Europe from 2009 to 2024. Lawyers argue that improving emissions control systems was feasible had manufacturers chosen to equip vehicles with larger tanks for AdBlue, a solution that mitigates NOx emissions.
The defendants have denied the use of illegal defeat devices, with some manufacturers questioning the accuracy of the allegations. The trial is expected to conclude by the end of the year, with further legal arguments scheduled for March 2026, while a judgment may be delivered by next summer.
Source: https://www.theguardian.com/business/2025/oct/13/carmakers-emissions-dieselgate-trial-mercedes-ford-renault-nissan-peugeot-citroen