Dieselgate claimants seek appeal over emissions ruling

Lawyers representing approximately 1.6 million motorists are seeking permission to appeal a High Court judgment regarding the ‘Dieselgate’ emissions litigation. The appeal application is scheduled to be heard on October 7 and 8, 2026.

The original July judgment followed a 13-week trial involving 20 leading carmakers, including Mercedes, Ford, Renault, and Nissan. The litigation alleges that manufacturers installed software to reduce the effectiveness of nitrogen oxide (NOx) emissions control during testing, leading to higher pollution levels during real-world driving.

Of the 20 vehicles examined, Lady Justice Cockerill found that only three—one Mercedes and two Peugeot/Citroën models—contained ‘Prohibited Defeat Devices’ (PDDs). The court ruled that the remaining 17 vehicles did not meet the legal definition of a PDD.

The claimants, led by law firms Leigh Day and Pogust Goodhead, are challenging the court’s interpretation of Article 3(10) of the Emissions Regulation 2007. They argue the judgment adopted an excessively narrow definition of a defeat device and conflicts with decisions made by the Grand Chamber of the Court of Justice of the European Union (CJEU).