Two major environmental campaigners, Mums for Lungs and ClientEarth, have just been given the green light by the High Court to play a part in the ongoing Dieselgate case – and it’s a significant step forward in the push for cleaner air and corporate accountability.
The campaign groups are asking to access documents that could reveal exactly how some diesel vehicles from big-name carmakers – including Mercedes-Benz, Ford, Renault, Nissan, and Peugeot Citroën – may have used hidden tech to cheat emissions tests.
The trial is due to kick off in October 2025, and this latest development means public scrutiny of the case could grow much sharper.
What’s the ‘dieselgate’ scandal about?
At the centre of it all are “defeat devices”, systems that allegedly helped cars pass emissions tests by lowering pollution levels during testing, only to pump out higher levels of nitrogen oxide (NOx) when on the road.
The result? Vehicles that met legal requirements on paper but may have been polluting well above the legal limits in real life.
Owners of these cars say they were misled. And now, with environmental groups stepping in, the conversation is shifting to the wider public health impacts too.
Public health and environmental impact
ClientEarth recently published a report revealing that these elevated emissions may be linked to around 16,000 premature deaths and have cost the UK up to £96 billion between 2009 and 2024.
These aren’t just numbers. They represent real lives, real health problems, and real strain on the NHS.
Jemima Hartshorn, founder of Mums for Lungs, put it powerfully: “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, campaigner at ClientEarth, added: “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.”
Why transparency matters
Both groups are asking for access to technical documents currently redacted or withheld. There’s concern that, without this transparency, much of the trial could happen behind closed doors. Today’s ruling doesn’t guarantee their access – that decision comes in July – but it does mean they won’t be hit with legal costs if the Court ultimately says no.
Join the fight for cleaner air and fairer treatment
If you bought or leased a diesel vehicle between 2009 and 2018, from brands like:
And more…
…you could be due compensation.
Find out more and check if you’re eligible to join the claim today.
