The Volkswagen emissions scandal, more commonly known as ‘Dieselgate’, remains one of the most significant corporate fraud cases in modern history. It not only exposed the lengths some car manufacturers would go to deceive regulators and customers, but also revealed the wider impact of corporate misconduct on public health and the environment.
Nearly a decade later, Dieselgate is far from over. The High Court in London is now hearing fresh claims against five other major carmakers accused of similar behaviour — marking one of the largest consumer and environmental justice cases ever brought in the UK.
The birth of a scandal
In September 2015, the United States Environmental Protection Agency (EPA) announced that Volkswagen had been using illegal software in their diesel engines to cheat emissions tests.
This “defeat device” software could detect when a car was undergoing emissions testing and activate full emissions controls to meet regulatory standards. However, during regular driving conditions, the software would deactivate or reduce the effectiveness of these controls, leading to nitrogen oxide (NOx) emissions up to 40 times higher than the legal limit.
The initial discovery was made by a small team of researchers at West Virginia University, who were conducting on-road tests of diesel vehicles. They found significant discrepancies between the emissions levels recorded during official tests and those observed in real-world driving. These findings prompted further investigations by the EPA, ultimately revealing the widespread use of defeat devices by Volkswagen and other car manufacturers.
Volkswagen’s admission to using defeat devices affected approximately 11 million vehicles worldwide, including nearly 1.2 million in the UK.
The fallout was immense. Volkswagen faced billions in fines, criminal prosecutions and reputational damage. In the UK, the company paid £193 million in compensation in 2022, with affected drivers receiving an average of £2,120 each. Globally, Volkswagen has paid more than £27 billion in settlements, fines and buybacks.
The ongoing impact of Dieselgate
While Volkswagen has settled many of its lawsuits, Dieselgate has sparked a wave of investigations into other carmakers suspected of using similar technology.
In 2025, a major High Court trial began in London against Mercedes-Benz, Ford, Peugeot/Citroën, Renault and Nissan. These manufacturers are accused of installing software that manipulated emissions readings and misled both regulators and drivers about how clean their cars were.
The five companies deny any wrongdoing, insisting their vehicles met all legal and technical standards at the time of sale.
However, if the claims are upheld, the case could open the door for hundreds of thousands of UK drivers to receive compensation.
The trial is expected to run until the end of 2025, with further hearings in early 2026. A final judgment could follow by summer 2026.
A growing public health crisis
The environmental impact of dieselgate is substantial. NOx emissions are a significant contributor to air pollution, leading to smog and respiratory problems. The increased emissions from the affected vehicles contributed to air quality issues and had potential health implications for millions of people worldwide.
Recent research from the Centre for Research on Energy and Clean Air (CREA) has shed light on Dieselgate’s lasting impact in the UK. According to the study:
16,000 people in the UK have died prematurely due to excess pollution from diesel emissions
30,000 children have developed asthma linked to air quality issues
The UK has lost 800,000 working days to pollution-related illness
The total economic cost is estimated at £96 billion.
The researchers warn that a further 6,000 lives could be lost without urgent action to tackle the remaining high-polluting vehicles still on the road.
Some environmental lawyers, including those from ClientEarth, have criticised the UK’s slower response compared to the US, where manufacturers were fined heavily, forced to recall vehicles, and ordered to pay into pollution reduction funds.
What Dieselgate means for UK drivers
For years, diesel cars were marketed as the cleaner, more efficient alternative — and many buyers paid a premium for models promoted as “low-emission”.
In response to the scandal, some car manufacturers, including Volkswagen, initiated recalls to fix the affected vehicles. This involved updating the software and, in some cases, modifying hardware to ensure compliance with emissions standards. However, these fixes were not without controversy, as some owners reported reduced vehicle performance and fuel efficiency after the updates.
Drivers who purchased affected vehicles may have suffered financial losses due to:
Lower resale value
Increased fuel consumption and maintenance costs after recall fixes
Misleading marketing about environmental performance
Could you be affected?
If you bought, leased or financed a diesel vehicle between 2009 and 2020, your car could be among those under investigation — even if you’ve since sold it. Eligibility depends on your vehicle’s make, model, and registration year.
For those affected by the scandal, now is the time to find out if you could join a group action to hold the car manufactures accountable. Together, you can ensure that such a breach of trust never happens again.
Join the Claim connects consumers with SRA-regulated lawyers. Visit the claim page to check your eligibility if a claim is open with one of our trusted legal partners. If a group action has not yet been launched, you can register your interest and we’ll keep you informed if a partner firm decides to take a claim forward.
