Trial resumes on Dieselgate scandal claims

The ongoing High Court trial concerning legal claims against major car manufacturers over the Dieselgate scandal is set to resume at 10.30am on Monday 2 March 2026. Taking place at the Royal Courts of Justice in London, this epoch-making case is expected to span three weeks, running until Friday 20 March. With lawyers representing 1.6 million vehicle owners, it marks the largest group claim trial in English and Welsh legal history.

Since its inception last year, the trial has captivated public attention as it investigates serious allegations that diesel vehicles manufactured by leading brands such as Mercedes, Ford, Renault, Nissan, and Peugeot/Citroen were equipped with devices designed to evade emissions testing. Over the span of twelve weeks, from October to December 2025, the court heard evidence from both factual and expert witnesses regarding the supposed use of “cheat devices” and “prohibited defeat devices (PDDs)”. These devices reportedly enable cars to detect when they are undergoing official testing, adjusting their performance to meet legal emissions standards. However, when these vehicles are driven normally, they are alleged to emit significantly higher levels of harmful pollutants, thereby posing an increased risk to public health and the environment.

Due to the unprecedented nature and scale of these claims, the cases against the core group of lead defendants—Mercedes, Ford, Renault, Nissan, and Peugeot/Citroen—are being prioritised to streamline the legal process. This strategic move aims to alleviate the burden on resources while ensuring a fair progression of the case. Other manufacturers facing similar allegations include Vauxhall/Opel, Volkswagen/Porsche, Jaguar Land Rover, BMW, FCA/Suzuki, Volvo, Hyundai-Kia, Toyota, and Mazda.

The outcome of this lead case trial is anticipated to influence all subsequent cases related to the scandal, with a judgment expected to be delivered by summer 2026. Following that, a further trial is scheduled for autumn to determine the compensation levels potentially owed to affected vehicle owners. The formidable law firm Leigh Day, in collaboration with 21 other legal practices, is representing the collective interests of the 1.6 million plaintiffs in this transformative litigation.