Law firm claims individual drivers could receive as much as £10,000 in damages, but German parent company Daimler has promised to "vigorously defend" itself against any group action.
Up to one million Mercedes-Benz drivers in Britain could have been unknowingly releasing illegal levels of emissions into the air after the German carmaker allegedly installed devices in diesel vehicles that could cheat emissions tests, lawyers have claimed.
International law firm PGMBM has today filed a group action litigation claim against Mercedes parent company Daimler AG at Liverpool's High Court that alleges the carmaker installed 'defeat devices' in hundreds of thousands of vehicles sold in the UK for more than a decade. Lawyers from firms Slater and Gordon and Leigh Day have also confirmed that they are investigating a case on behalf of Mercedes-Benz drivers.
The auto giant has rejected the allegations.
Defeat devices detect when an engine is being emissions tested and temporarily limit the amount of nitrogen oxide in the exhaust in order to meet required standards. They were at the centre of the so-called 'dieselgate' scandal in 2015, which revealed how German auto giant VW was systematically cheating emissions tests.
PGMBM now alleges that Mercedes has manufactured cars and vans whose real-world diesel emissions are as much as 10 times higher than EU and UK limits. The case alleges that drivers were misled about the green credentials of their vehicles and may have had to shoulder higher fuel bills and maintenance costs than anticipated.
Nitrous oxide is a significant factor in air pollution and respiratory conditions, particularly in young and vulnerable people; the Royal College of Physicians estimates that illegal levels of air pollution results in over 40,000 early deaths per year.
"This case highlights how Mercedes has abused the trust of its customers by egregiously misleading them in the pursuit of profit," said PGMBM managing partner Tom Goodhead. "We believe that Mercedes must be held to account for its unlawful and deceitful actions, and this case will give consumers the opportunity to do so, and be compensated for being misled by a supposedly trustworthy company."
Daimler AG has strongly refuted the allegations. A spokesperson said: "We believe that the claims are without merit and will vigorously defend against any group action."
The technology at the centre of the case is called AdBlue, the exhaust fluid that can be added to diesel engines to reduce emissions. Mercedes uses a software system that controls the injection of the solution into diesel exhaust to break down the nitrogen oxides produced by the engine and convert them into inert nitrogen and water. The company claimed that the software would result in its "cleanest diesel cars ever".
However, PGMBM claims the software can be programmed to lower the amount of AdBlue being injected after a prescribed time, leading to much higher nitrogen oxide emissions in real-world driving conditions than those demonstrated under test conditions.
PGMBM claims individual car owners could receive up to £10,000 in compensation and the overall case could see Daimler dishing out £10bn in damages.
Its claim comes after roughly 90,000 Audi, Seat, VW, and Skoda diesel vehicle drivers in England and Wales won the first round of their High Court legal battle with German parent company Volkswagen Group in early April. The presiding judge ruled that the software installed in their cars did qualify as a 'defeat device' - a conclusion Volkswagen contests.
The troubled German automotive industry is still battling a long-running wave of litigation following the 'dieselgate' scandal that erupted in 2015 following the revelation that Volkswagen sold around 11 million diesel cars - of which 1.2 million were in the UK - equipped with a defeat device. A host of other auto manufacturers were subsequently accused of operating similar devices.
Daimler instituted a voluntary recall of three million of its diesel vehicles manufactured to Euro 5 and Euro 6 emissions standards in 2017. But just a year later, Germany's motor authority Kraftfahrt-Bundesamt found that some 280,000 Mercedes-Benz vehicles had been fitted with illegal defeat devices, leading to a further recall of 670,000 affected vehicles across Europe.
The firm continues to face litigation worldwide for its part in the scandal and was fined €870m as part of a settlement with German prosecutors last year.
The Environmental Protection Agency in the US is also currently investigating Daimler, according to PGMBM.