Nine years of Dieselgate - from the High Court to recalls and the risk to people’s health

Leigh Day is currently pursuing claims on behalf of hundreds of thousands of car users against vehicle manufacturers who have allegedly installed devices to manipulate the vehicles’ emissions controls and cheat emissions tests.

‘Defeat devices’ were allegedly fitted to vehicles to artificially reduce emissions in order to pass EU tests. When vehicles fitted with these devices are driven on the road, it’s claimed they emit many times more levels of toxic nitrogen oxide (‘NOx’) gases than under test conditions. 

Recently, after environmental law group ClientEarth submitted a freedom of information request, the Department for Transport (‘DfT’) confirmed it is investigating prohibited defeat devices in 47 types of diesel cars registered from 2009 to 2019. This is just the first part of the DfT’s investigation; it is believed there may be 200 or more models in the UK with defeat devices, potentially between two and six million cars on the roads. Emily Kearsey from ClientEarth told the Times, “Excess emissions from vehicles are contributing to air pollution, which we know is the biggest threat to public health in the UK. This is an invisible killer that’s shortening people’s lives and reducing their quality of life.”

Recalls

At the time the Dieselgate scandal broke in 2015, the UK government did not have the power to recall vehicles for environmental nonconformity. This gap was addressed by implementing sections 74-77 of the Environment Act 2021, as introduced in May 2024. This provided wide-ranging new powers that would allow the Secretary of State for Environment, Food and Rural Affairs to compel manufacturers to recall vehicles which the Secretary of State has reasonable grounds to believe do not meet relevant environmental standards.

The Act was envisioned as a tool to compel vehicle manufacturers to ‘recall their products 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’.

Impact on individuals and the environment

The UK Health Security Agency reports that increased levels of NOx contributing to air pollution is the largest environmental risk to UK public health. Long-term exposure to these gases is linked to 26,000 to 38,000 premature deaths annually in England, severely affecting children’s lung development and contributing to heart disease, asthma exacerbation, strokes, and cancer in adults.

Even short-term exposure to high levels of NOx gases can cause a range of adverse health effects including exacerbation of asthma, effects on lung function, increases in hospital admissions and mortality.

These gases are not only harmful to human health, but also have a detrimental effect on the environment, impacting ecosystems and agricultural crops. Ground-level ozone pollution, which is formed by NOx gases, is shown to be toxic to plants and contributes to loss of biomass, crop yields, and forest productivity.

Leigh Day co-leading on legal action of unprecedented scale

Leigh Day is jointly leading the groundbreaking Dieselgate legal claims, representing more than 220,000 diesel vehicle owners in claims against the major vehicle manufacturers alleged to have cheated emissions tests. In total, more than 1.2 million vehicle owners are involved in the legal action – the biggest group claim ever to come before any of the UK courts.

After a series of major High Court hearings over the last 11 months, the High Court has ruled the first Dieselgate trial will be that of cars manufactured by Mercedes, Ford, Nissan/Renault, and Peugeot/Citroën, which will take place in October 2025.

In total, Leigh Day is pursuing claims against nine major vehicle manufacturers, which, in addition to the above, include Jaguar/Land Rover, the Volkswagen Group, BMW, Volvo and Vauxhall. Leigh Day has a history of holding major corporations to account and were the joint-lead lawyers in the first diesel emissions group litigation brought against the Volkswagen Group on behalf of over 90,000 vehicle owners.

How can I be involved?

We are still accepting Volvo claims and if you owned or leased a Volvo diesel vehicle since 2009, you may be eligible to join the legal claim for compensation.

Checking whether you’re eligible to join the claims is free, quick and easy to do – just click here.