Campaign groups join Dieselgate legal fight

The High Court today allowed two environmental campaign groups, Mums for Lungs and ClientEarth, to move forward with their requests to participate in the Dieselgate litigation, acknowledging the significant public interest in uncovering the ongoing ramifications of the Dieselgate scandal. A recent report commissioned by ClientEarth revealed that the elevated emissions associated with the use of prohibited defeat devices have been linked to approximately 16,000 premature deaths and £96 billion in costs within the UK from 2009 to 2024.

Scheduled for trial in October 2025, this case aims to determine whether certain diesel vehicles from manufacturers like Mercedes-Benz, Renault, Nissan, Peugeot Citroën, and Ford were fitted with devices designed to manipulate NOx emissions during testing to meet legal limits. Vehicle owners claim these defeat devices allowed the cars to appear compliant while actually exceeding emissions targets.

In their applications, Mums for Lungs and ClientEarth, which are not formal parties to the litigation, are requesting access to pertinent documents that outline how these alleged devices operated and the effects they had on emissions, specifically regarding the conditions in which they functioned. Currently, much of this information is either redacted or kept confidential, raising concerns that the upcoming trial may need to be largely conducted behind closed doors if these barriers remain in place. Today's ruling ensures that the organisations will not be liable for the costs of other parties if their applications are denied at a forthcoming hearing in July.

Jemima Hartshorn, Founder of Mums for Lungs, remarked, “I founded Mums for Lungs because of the huge health impact air pollution has, particularly on children. Children across the country are growing up with stunted lungs and asthma caused by air pollution, tens of thousands of children are admitted to hospital every year struggling for their breath which is so scary, and they then miss school, playing with their friends, having dinner at home with their family. Diesel cars are a major contributor to air pollution. We are all affected by air pollution, every breath we take, and the public therefore has a direct interest in understanding the circumstances in which any alleged historic defeat devices operated and what alleged impact these devices have had, including whether they resulted in NOx emissions above the legal limits.”

Andrea Lee, a campaigner at ClientEarth, stated, “Dieselgate has already cut thousands of lives short and placed a huge burden on public health and the NHS. For too long, auto manufacturers have tried to sweep this scandal under the rug. This case could finally bring crucial information to light and reveal the true scale of what happened. Public access to this material is essential, not just to ensure justice is done, but to help guide government investigations and ensure action is taken to finally clean up this mess.”

Shazia Yamin, a Partner at Mishcon de Reya representing Mums for Lungs and ClientEarth, expressed her support for the Court ruling. “We welcome today's Court ruling to grant some cost protection to our clients. Securing this protection was important as without it, there was a significant risk that our clients would not be able to proceed with their applications, which are brought in the interests of the wider public and open justice. We look forward to the next step which will be a hearing in July to decide whether public access to the information sought by our clients is granted.”