A significant legal battle is unfolding in London's High Court, where a pivotal trial commenced on Monday, accusing several major car manufacturers of allegedly cheating diesel emissions tests. This lawsuit, one of the largest mass legal actions in English history, involves 1.6 million claimants in total, with approximately 850,000 specifically targeting five manufacturers: Mercedes-Benz, Ford, Nissan, Renault, and Stellantis-owned brands Peugeot and Citroen.

The core of the accusation revolves around the alleged use of unlawful 'defeat devices'. Claimants' lawyers assert that these devices were designed to detect when vehicles were undergoing official emissions tests, ensuring compliance with legal limits. However, they contend that these systems were deactivated or operated differently when the cars were on public roads, leading to higher actual emissions. This legal challenge emerges a decade after the infamous Volkswagen 'dieselgate' scandal, which resulted in billions of euros in fines, compensation, and legal costs for VW, including criminal charges against its former CEO, Martin Winterkorn.

In response to these serious allegations, the implicated manufacturers vehemently deny the claims, asserting they are fundamentally flawed and rejecting any comparison to the VW scandal. Mercedes-Benz, for instance, has stated that its emission control systems are both legally and technically justified. The ongoing trial will initially focus on a small sample of diesel vehicles from the five primary manufacturers to ascertain whether prohibited defeat devices were indeed employed. The court's findings in this phase will be legally binding for hundreds of thousands of similar claims against other automakers, including Stellantis-owned Vauxhall/Opel and BMW. Should the court rule in favor of the claimants, the determination of damages would be addressed in a subsequent trial next year.

This is not the first instance of such litigation in London; the High Court previously ruled against Volkswagen in 2020, although VW later settled those claims without admitting liability in 2022. The current collective litigation against 14 manufacturers is considerably larger, with claimants' lawyers estimating its overall value to be around 6 billion pounds. Beyond the UK, automakers are confronting similar legal challenges globally. Notably, a court in the Netherlands ruled in July that diesel cars sold by Stellantis brands Opel, Peugeot-Citroen, and DS contained defeat devices, a judgment that Stellantis has disputed. Furthermore, manufacturers and suppliers have faced fines and reached settlements in the United States and other regions concerning investigations into diesel vehicle emissions, underscoring the widespread impact of this issue.