Carmakers Go on Trial as 1.6 Million UK Drivers Seek Justice
Five major manufacturers face allegations of emissions cheating in what lawyers call the largest class action in English legal history.
A major lawsuit against five leading carmakers accused of cheating on emissions tests opened at the High Court in London on 13 October 2025. The trial represents the latest chapter in what has become known as the "dieselgate" scandal.
The Largest Class Action in English Legal History
Lawyers describe the case as the largest class action in English and Welsh legal history. It could eventually involve 1.6 million car owners pursuing claims totalling an estimated £6 billion in damages, according to Consumer Voice.
The five lead defendants — Mercedes, Ford, Peugeot/Citroën, Renault and Nissan — were chosen by the court to be tried first due to the scale of the litigation. They face allegations from 880,000 car owners that they used illegal software to manipulate emissions test results. All five manufacturers deny the accusations.
What Was Said in Court
Opening the trial, Thomas De La Mare KC, representing the car owners, told the court that car manufacturers decided they would "rather cheat than comply with the law" over vehicle emissions. He argued that "each player in the industry basically took a conscious decision that customer convenience, which helped the industry sell more cars, was more important" than preventing pollution (BBC News).
The manufacturers have strongly contested the claims. Alexander Antelme KC, for Renault, described the allegations as "without merit and untenable" in written submissions, stating that the features in question are "appropriate and necessary elements of a well-designed diesel engine." Neil Moody KC, for Ford, called the case "scientifically illiterate" and "flawed on the facts and the law" (BBC News).
Background: The Dieselgate Scandal
The scandal first emerged in September 2015, when the US Environmental Protection Agency accused Volkswagen of installing software — known as "defeat devices" — on diesel cars to lower readings of nitrogen oxide emissions during official tests. When the cars were driven on the road, the pollution control systems were turned off to improve performance, resulting in significantly higher levels of pollution than official figures suggested.
Volkswagen later admitted the devices had been used deliberately and had been fitted to approximately 11 million cars worldwide. The company has since paid out more than €32 billion (£27.8 billion) in fines and compensation globally, mostly in the US (BBC News).
In 2020, the High Court ruled that Volkswagen had used defeat devices in breach of European Union rules to pass emissions tests. This led to a separate settlement of £193 million for 91,000 British motorists.
Other Manufacturers Facing Claims
Depending on the outcome of this trial, nine additional carmakers face similar claims, including Vauxhall/Opel, Volkswagen/Porsche, Jaguar/Land Rover, BMW, FCA/Suzuki, Volvo, Hyundai-Kia, Toyota, and Mazda (Leigh Day).
What Happens Next
The main trial before Lady Justice Cockerill is due to conclude in December 2025, with legal arguments to be heard in March 2026. A judgement is not expected until summer 2026 (BBC News).
A separate compensation trial is scheduled for spring 2026 (Leigh Day).
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