The High Court has dealt a major blow to 1.6 million car owners who claimed that manufacturers fitted their vehicles with devices designed to cheat emissions tests, in a case known as 'dieselgate'. Lady Justice Cockerill ruled that the majority of allegations against Nissan, Ford, and Peugeot were unfounded, stating that "in the majority of instances, the court found that the relevant strategy did not constitute a prohibited defeat device" – software engineered to make an engine behave differently under test conditions.
However, her judgment also identified that certain technologies in some Mercedes and Peugeot-Citroën vehicles could potentially be classified as prohibited defeat devices. Both companies acknowledged these findings but indicated they are considering appeals regarding the specific vehicles deemed non-compliant. In contrast, Nissan and Renault welcomed the overall ruling, stating their vehicles comply with all applicable regulatory requirements.
The 15-week trial focused on 20 vehicle models sold by five manufacturers – Mercedes, Ford, Renault, Nissan, and Peugeot/Citroën – from 2009 onwards. Lady Justice Cockerill's verdict is significant not only for the UK but also has implications for other manufacturers in Europe. She stressed that proving an intent to rig a test was necessary, stating "It was not enough for the claimants simply to establish that the challenged strategies reduced the effectiveness of emissions-control systems outside the relevant testing conditions."
Lawyers representing the claimants expressed disappointment with the outcome and are now considering an appeal. They argue that the judgment creates a divergence between the legal interpretation of 'defeat devices' in Great Britain and much of Europe, where similar devices might be deemed illegal. This could have broader implications for future environmental and consumer protection cases within the UK.