Lady Justice Cockerill has handed down a 369-page ruling that rejects the vast majority of allegations in the largest group action trial in English legal history – but finds that some Mercedes-Benz and Peugeot-Citroën vehicles contained prohibited defeat devices.
The judgment, delivered on Thursday after a ten-week trial that concluded in March, dealt a blow to around 1.6 million motorists who had sued more than a dozen car manufacturers, claiming that diesel vehicles made from 2009 onwards were fitted with software designed to cheat emissions tests. The case focused on 20 sample vehicles from five manufacturers: Mercedes-Benz, Renault, Nissan, Ford, and Peugeot-Citroën.
“High Court rejects most dieselgate claims against carmakers but finds Mercedes and Peugeot-Citroën used defeat devices.”
In her ruling, Cockerill said that “in the majority of instances, the court found that the relevant strategy did not constitute a prohibited defeat device”. She added: “The court rejected most of the principal allegations advanced against the manufacturers whose vehicles were examined at trial.”
The judge made clear that proving intention to rig a test was essential. “For a defeat device to be found, there needs to be an intention to cause the emissions control system to operate differently when it senses it is being tested,” she said. “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.”
However, the ruling did not entirely exonerate the industry. Cockerill found that one strategy used in Mercedes cars, which was removed in 2015, and another used in some Peugeot-Citroën vehicles, did constitute prohibited defeat devices. Mercedes welcomed the verdict overall but said it disagreed with the finding of non-compliance. “In our view, the emission control software functionalities are justifiable on both technical and legal grounds,” the German carmaker said. “We are actively considering all of our available options, including a potential appeal.” Stellantis, owner of Peugeot-Citroën, said it too was considering an appeal.
Barristers for the motorists had argued that the devices allowed cars to detect emissions testing and reduce harmful nitrogen oxide output only under test conditions. But the judge noted that “testing, however, is difficult to interpret and none of the approaches to isolating the effect of a particular calibration on NOx was entirely satisfactory”.
Significantly, Cockerill added that “if an alternative approach to the meaning of ‘defeat device’ were taken, a larger number of defeat devices would be established, including devices in each of the lead manufacturers cars”. James Oldnall, managing partner at Milberg, which represented some of the claimants, said: “We are pleased that the court has ruled that Mercedes installed illegal defeat devices, just like Volkswagen.” Claimants’ lawyers said they were considering an appeal, arguing the judgment created a significant divergence between the legal position in Great Britain and much of Europe.
The ruling now raises the prospect of further legal battles as both sides weigh their next moves – and as the 1.6 million car owners wait to see whether any of them will receive compensation.