Major carmakers go on trial over ‘dieselgate’ emissions cheat claims
A landmark legal battle will begin in the Supreme Court on Monday as five major carmakers are accused of cheating on emissions tests.
The hearing marks a significant development in the ongoing ‘dieselgate’ scandal, with the potential to affect 1.6 million vehicle owners in what lawyers describe as the largest class action in English and Welsh legal history.
Companies are facing allegations that they used software that allowed their vehicles to reduce harmful gas emissions under test conditions.
The five automakers involved include Mercedes, Ford, Peugeot/Citroën, Renault and Nissan, all of which deny the accusations. They are accused by 220,000 vehicle owners of misleading them about emissions tests.
Five companies were selected by the court as the primary defendants to be tried first. Depending on the outcome of the case, nine other automakers could face similar claims.
These are: Opel and Vauxhall, Volkswagen and Porsche, Jaguar Land Rover, BMW, FCA and Suzuki, Volvo, Hyundai/Kia, Toyota and Mazda.
The “Dieselgate” scandal dates back to September 2015, when Volkswagen was accused by the US Environmental Protection Agency of installing software in diesel cars to reduce nitrogen oxide emissions.
Known as “defeat devices”, the Supreme Court ruled in 2020 that Volkswagen’s use of the software violated the European Union’s requirements for emissions testing.
The carmaker settled a class action out of court and paid £193 million to 91,000 British drivers. To date, the company has paid out more than £27.8bn as a result of the scandal, the majority of which is in the US.
Starting Monday, the Supreme Court will decide whether the systems installed in diesel cars by five automakers are similarly designed to circumvent clean air laws.
They face allegations that defeat devices were used to detect when a car was in a test scenario. This causes it to run its engine at a lower power level, meaning lower nitrogen oxide readings are recorded.
Lawyers representing the drivers claim their clients have been deceived about the environmental impact of the vehicles and that their continued presence on the roads means dangerous levels of pollution continue to be emitted.
A decision is not expected until summer 2026. If the court rules against the automakers, the next hearing to determine compensation payments to those affected is likely to be held in Fall 2026.
Martyn Day, of Leigh Day, one of 22 law firms representing drivers, said: “Ten years after the diesel scandal first emerged, 1.6 million UK motorists now have the chance to determine at trial whether their vehicles contain technology designed to cheat emissions tests.”
He added that if the allegations against car companies were upheld in court, it would “demonstrate one of the most egregious breaches of corporate trust in modern times.”
“This could also mean that people in the UK are breathing in far more harmful emissions from these vehicles than they are told, potentially putting the health of millions more at risk.”
Those taking legal action have either bought, leased or otherwise acquired a diesel vehicle manufactured by one of the companies, most of which are based in England and Wales, but some are based elsewhere in the UK.
Mercedes owner Adam Kamenetzky said: “If these allegations are true, regulators, politicians and the public have been deceived by manufacturers who allegedly profit from sales of diesel cars in defiance of clean air laws and measures aimed at improving public health, such as Ulez.”
The companies involved in the case deny the allegations.
