Several of the world’s major automakers — including Mercedes-Benz, Ford, Nissan, Renault, and Stellantis brands Peugeot and Citroën — face a pivotal trial at London’s High Court over allegations of systematically cheating diesel emissions tests.

Lawyers representing approximately 1.6 million vehicle owners contend that these companies installed “defeat devices” that masked emissions during official testing, but allowed far higher pollution levels during normal driving.

The case underscores not merely questions of corporate ethics, but the broader regulatory and environmental challenges of our time. The manufacturers reject the claims, arguing their systems were legally compliant and technically justified, and they distance themselves from the Volkswagen “Dieselgate” scandal of 2015, which cost VW over €32 billion in fines and settlements.

The trial will initially assess a limited number of vehicles, with any determination of damages deferred to a subsequent hearing. Its outcome will have cascading effects, potentially shaping hundreds of thousands of related claims against other manufacturers, including BMW and Vauxhall/Opel.

Beyond legal liability, the case highlights the ongoing tension between corporate profit motives, regulatory oversight, and public welfare — demonstrating how systemic lapses in accountability can translate into profound environmental and societal costs.

Valued at roughly £6 billion, this represents one of the largest mass actions in UK legal history, with similar proceedings underway internationally.