Ten years on, and the aftershocks of Dieselgate are still being felt, with the biggest class action ever brought against car manufacturers set to take place later this year.
The Prohibited Defeat Device Trial, involving 1.5m diesel owners, is set to begin in October 2025 and will determine whether Mercedes-Benz, along with manufacturers such as Ford, Nissan/Renault, and Citroën/Peugeot, used illegal defeat devices in their diesel vehicles.
The original Dieselgate has its origins in 2015, when the US EPA accused Volkswagen of violating the Clean Air Act. They found VW had programmed their cars so that the emission control systems only operated during laboratory tests, in order that NOx emission were seen to meet US standards.
Under real-world driving conditions however, the vehicles emitted up to 40 times more NOx. The defeat devices had been fitted in around 11 million cars worldwide.
Now we jump forward to 2024 when environmental law group ClientEarth submitted a freedom of information request, in response to which the Department for Transport revealed that it currently is investigating similar defeat devices in 47 types of diesel cars registered between 2009 and 2019.
It is thought there may be around 200 models in the UK with such devices, which would mean somewhere between two and six million cars .
In response to this lack of certainty, Mums for Lungs have written to the judge asking that documents related to the case to be made public due to their significance.
Jemima Hartshorn, founder of the Mums for Lungs campaign group (pictured above), said: ‘This looks like a sequel to the original Dieselgate, in which car manufacturers across the world were found to have installed defeat devices in their cars, to hide that these were emitting illegal levels of toxic gases.
‘These cars are still on our roads polluting our towns and cities and making our children sick. We deserve to understand what is going on now, we need these documents to be made publicly available due to the significant public interest in this matter.’
The letter reads, in part:
We understand that in this class action, documents relating to the litigation are currently being held in confidentiality orders. We write to request that the documents be made publicly available sue to the significant public interest in this matter.
Defeat devices that might still be used in diesel vehicles result in these vehicles emitting illegally high levels of NOx when used in the real world.
The public must be given full access to documents and reasonings in this court case, because our health depends on the air we breathe and the emissions around us.
It is signed by Asthma and Lung UK, the Ella Roberta Foundation, Global Action Plan, Evelina London Children’s Hospital, Transport and Environment UK, the UK Health Alliance on Climate Change, Parents for Future UK, Mothers Rise Up, Global Black Maternal Health among others.
Mums for Lungs are also calling for the manufacturers to recall all affected cars immediately and for them to set up a fund, of least £1 billion, to help support the phasing out of all diesels.
Since May 2024, the Government have had the power – under sections 74-77 of the Environment Act – to force manufacturers to recall cars ‘for reasons of environmental failure or non-conformity [providing] a safeguard against such future issues with a vehicle in the case that the manufacturer or economic operator was unwilling to recall vehicles’.
In 2023, research undertaken by the International Council on Clean Transportation using data from official government tests across the UK and EU, found that 77% of Euro 6 diesel cars (those supposedly conforming to the current EU emissions rules) and 85% of the older Euro 5 cars returned test results they described as ‘suspicious’ suggesting the likely use of a defeat device.
Rosamund Adoo-Kissi-Debrah CBE, Founder of the Ella Roberta Foundation said: ‘The air we breathe in the U.K. is toxic, but the public cannot see it because it is invisible. We know that NOx emissions from vehicle exhausts are a major source of air pollution in the U.K. What is worse it seems, is some cars we drive are more polluting than we believe or are being told. I believe that is wrong. For the public to be mislead is unforgivable, and I hope through this court process that car manufacturers will be held to account.
‘Air pollution is killing people, it is causing horrific damage to people’s health and I believe we all have a right to breathe safe, clean air. Air pollution from vehicle exhausts killed my daughter Ella, and I want to ensure no other families have to suffer like she did, like we continue to suffer without her in our lives.’
Photos: Mums for Lungs / Crispin Hughes