UK drivers sue carmakers over diesel test ‘cheating’ in £6bn case

British drivers are taking some of the world’s biggest carmakers to court, accusing them of cheating emissions tests and harming both people and the planet.

The class-action case involves over 1.6 million diesel car owners who say the companies used illegal “defeat devices” that made pollution appear lower in lab tests than on the road. The case could cost manufacturers as much as £6 billion ($8 billion) if the court rules in favour of the claimants.

At the heart of the trial are vehicles made between 2012 and 2017 by Mercedes-Benz, Ford, Nissan, Renault, Peugeot, and Citroën, all part of the Stellantis group. Lawyers say those cars release up to 12 times more nitrogen oxide (NOx) during normal driving, contributing to dirty air linked to thousands of premature deaths in the UK each year.

“These companies would rather cheat than comply with the law,” said lawyer Tom de la Mare, representing the claimants. “They made a conscious choice to prioritise profits and convenience over people and the environment.”

Carmakers push back

The manufacturers reject the accusations, calling them “fundamentally flawed.” They argue that their emission systems are designed to behave differently in certain conditions for safety and performance reasons.

“Not every emissions system is a cheat,” said Alexander Antelme, lawyer for Renault. “The claimants assume Volkswagen’s case applies across the whole industry, but that is false.”

Automakers also argue that lowering NOx can increase other harmful gases. “There are trade-offs,” Antelme added. “Engines must operate safely and efficiently in real-world conditions.”

Echoes of ‘Dieselgate’

The case comes ten years after Volkswagen’s “dieselgate” scandal, which cost the company more than €32 billion ($37 billion) in fines, refits, and legal costs. VW admitted in 2015 to using defeat devices, sparking global outrage and tighter scrutiny of diesel technology.

This new trial, among the largest mass claims in UK history, will focus on 20 sample vehicles. A ruling is expected in mid-2026, and the judgment will guide decisions in another 800,000 related claims, including cases against BMW and Vauxhall/Opel.

While VW settled its UK claims in 2022 without admitting guilt, the new defendants say they are not the same. “We reject the long shadow of dieselgate,” a spokesperson for one manufacturer said.

What’s at stake

The lawsuit could reshape trust in diesel technology and corporate transparency. For many car owners, it’s about fairness and accountability.

Environmental groups say the case could push carmakers to speed up their move to electric vehicles and stricter emission compliance worldwide.

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