A High Court judgement in the ‘Dieselgate 2’ case has mostly cleared the manufacturers involved, although specific findings have been made against Mercedes-Benz and Peugeot/Citroen.
The Pan-NOx Diesel Emissions Group Litigation – the biggest ever class action in the UK, with more than 1.6 million motorists involved – alleged that certain diesel vehicles were equipped with ‘defeat devices’ which reduced the effectiveness of their emissions control systems outside of official testing conditions, resulting in higher nitrogen oxide emissions during normal vehicle use.
The manufacturers denied the allegations, contending that their vehicles complied with the applicable regulatory framework.
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The High Court trial heard allegations against Mercedes, Ford, Renault, Nissan and Peugeot/Citroen – manufacturers which were chosen by the court as lead defendants, whose cases were heard ahead of other manufacturers’ cases to save time and reduce costs.
In its written judgement, the court has rejected most of the principal allegations against the manufacturers, and stated that in the majority of cases the strategies they used did not constitute a prohibited defeat device.
However, the court did make adverse findings in relation to a ‘coolant temperature setpoint’ device in Mercedes cars, which was removed from vehicles by a December 2015 update, and a ‘split-injection’ strategy used in some Peugeot-Citroën Euro 5 vehicles.
The court also stated that if an alternative approach to the meaning of ‘defeat device’ was taken, a larger number of such devices would be established, including devices in each of the lead manufacturers’ cars.
A further trial is due to take place in October 2026 to determine the consequences of any actionable breaches and any issues relating to damages or other remedies.
Mercedes may appeal judgement
In a statement issued in response to the judgement, Mercedes-Benz said: “We welcome that the English High Court ruled very largely in favour of Mercedes-Benz. The court came to the conclusion that all of the sample vehicles are compliant with the relevant European emissions legislation on defeat devices, following the application of software updates. This also confirms the effectiveness of our software update programme.
“The English High Court also decided that it considers only one out of four of the sample vehicles as non-compliant in one functionality before the relevant software updates. This functionality was remedied with the respective software update, which was also confirmed by the court.
“We respect the court’s decision concerning this functionality but disagree with this finding. In our view, the emission control software functionalities are justifiable on both technical and legal grounds. We are actively considering all of our available options, including a potential appeal.”
A statement from Renault Group reads: “Renault Group welcomes this decision, which is fully consistent with its long-held position that its vehicles have been and are designed, engineered, and manufactured in accordance with all applicable regulatory requirements.
“Renault Group will now pursue the recovery of its legal costs from the large institutional insurers and hedge funds who backed these claims in the hope of a financial gain.”
Potential for claimants to appeal
Martyn Day, senior partner at Leigh Day, on behalf of its claimants against Mercedes, Ford, Renault, Nissan and Peugeot/Citroen, said: “The High Court has found that despite their denials, other manufacturers also used VW-style defeat devices. The Judge has also found that many other defeat devices are lawful because she surprisingly disagreed with the established EU case law on what a defeat device is.
“If this ruling is followed in Great Britain then this is now the only significant place in Europe where manufacturers are free to build and sell cars that contain these types of devices.
“We welcome some of the Judge’s findings, but we think important parts of the decision are disappointing not least because of the impact on the environmental and consumer protection. We are considering with our clients whether to apply for permission to appeal.”
Anna Varga, partner at Pogust Goodhead, on behalf of its claimants against Mercedes, Ford, Renault, Nissan and Peugeot/Citroen, said: “Today’s judgment does not bring this litigation to an end. The court has found that certain manufacturers installed unlawful defeat devices, but it also adopted a significantly narrower interpretation of the law than that applied elsewhere in Europe. It is that interpretation, and the important legal issues flowing from it, which will now require careful consideration.
“Our responsibility is unchanged. We represent 1.6 million motorists who are entitled to have their claims pursued with determination and rigour. We will continue working closely with our co-lead firms and leading counsel to assess the judgment, consider the appropriate next steps and ensure every properly arguable avenue remains available to our clients.
“This litigation has always been about accountability. That principle has not changed today, and neither has our commitment to the people we represent.”