The High Court has delivered a mixed verdict in the UK’s largest-ever group action, largely ruling in favour of five major car manufacturers accused of using illegal defeat devices to cheat emissions tests.
In a judgment handed down in the last hour (10th July), Justice Sara Cockerill said the court had ‘rejected most of the principal allegations advanced against the manufacturers whose vehicles were examined’ at trial.
The case, brought on behalf of 1.6 million motorists, had alleged that Mercedes-Benz, Ford, Renault, Nissan and Stellantis-owned Peugeot-Citroën fitted devices that reduced the effectiveness of emissions control systems outside regulatory testing conditions, resulting in higher nitrogen oxide emissions during normal driving.
Eleven years after the Dieselgate scandal first erupted – when Volkswagen admitted fitting millions of vehicles with software to manipulate emissions tests – the ruling marks a significant setback for campaigners. The court found that, in the majority of cases, the manufacturers’ strategies did not constitute a prohibited defeat device.
However, the judgment was not a complete victory for the industry. Justice Cockerill made ‘adverse findings’ against two manufacturers specifically. A ‘coolant temperature setpoint’ device in Mercedes cars and a ‘split-injection’ strategy used in some Peugeot-Citroën Euro 5 vehicles were found to be non-compliant.
The judge also noted that ‘if an alternative approach were taken to the meaning of ‘defeat device’ most of the allegations would still fail’, suggesting a broader interpretation could have yielded a different outcome.
A further trial is scheduled for October 2026 to determine damages in relation to the actionable breaches identified.
Mums for Lungs referred to the judgment as ‘bizarre and occasionally contradictory’ and said said it would continue to fight for little lungs. They also called for manufacturers found at fault to act swiftly to remove their vehicles and compensate for their actions.
The ruling, binding on a further 800,000 similar claims against other manufacturers including Jaguar Land Rover, Toyota, and BMW, now shifts focus to the October damages trial, where the two car companies found to have breached regulations will face potential compensation claims.
Jemima Hartshorn, Founder and Director of Mums for Lungs, said: ‘This is one setback, but we will not give up on our campaign. Whatever the courts have found, it does not change the scientific consensus – that these diesel cars are toxic. We will continue to fight for little lungs, the science is clear even if the courts are not. It’s important that the two car companies found guilty today act swiftly to remove their vehicles and compensate for their actions.
‘If the courts will not act, we need the Government to urgently conclude its investigation which it has today promised to continue.
‘For more than a decade, families have been left breathing the consequences of one of the biggest corporate scandals in automotive history. There will be another court case in October, and we will continue pressing the new Government under Andy Burnham to act.
‘We need to understand why there has been clear action in Germany and the US but the UK courts have taken a different view – that makes no sense to ordinary parents like us.
‘Other countries acted. Executives faced justice, manufacturers paid billions, and dirty vehicles were taken off the roads. In the UK, we’ve had delay after delay while millions of polluting cars remain in use. It is time for ministers and judges to stop dragging their feet and put public health first.’
Photo: Ron Fassbender