Mercedes-Benz owners could demand compensation in a High Court class action alleging that the German premium carmaker used a ‘defeat device’ system to cheat diesel emissions tests.

International law firm PGMBM has filed a group litigation claim in the Liverpool High Court against Daimler AG, the parent company of Mercedes-Benz UK, which it believes could be worth up to £10 billion.

Its action came as Slater and Gordon and Leigh Day, the law firms behind a similar group action against Volkswagen in the aftermath of the “dieselgate” emissions scandal, confirmed that they are also investigating the possibility of legal action against the OEM.

Last month around 90,000 motorists who bought or leased affected diesel-powered VW, Audi, Seat and Skoda vehicles won the first round of their legal battle after High Court judge, Mr Justice Waksman, ruled that the Volkswagen Group had installed unlawful “defeat devices” in thousands of its EA189 diesel engines between 2007 and 2015.

PGMBM argues that Mercedes-Benz has allegedly misled customers, the public and authorities concerning the amount of toxic emissions produced by certain models of their diesel cars and vans produced between 2007 and 2018 in legal papers filed with the Liverpool High Court on Friday (May 8).

Its claim alleges that Mercedes committed a fraud by manufacturing cars and vans whose real-world diesel emissions exceed the limits imposed by EU and UK laws by up to 10 times.

In July 2017, Daimler instituted a voluntary recall of three million of its diesel vehicles manufactured to Euro 5 and Euro 6 emissions standards.

The following year Germany’s motor authority Kraftfahrt-Bundesamt found that some 280,000 Mercedes-Benz vehicles had been outfitted with illegal defeat devices, leading to a wider recall of affected vehicles across Europe.

As part of a settlement with German prosecutors over its diesel emissions scandal, Daimler AG was fined €870m (£761.8m) in 2019.

PGMBM said that there are currently tens of thousands of cases involving Mercedes-Benz’s actions pending in courts around the world, including claims for damages and the right to return the vehicle without any financial losses by the owner.

Damages awarded have typically been over £10,000 per vehicle, it said.

PGMBM estimates that up to half a million vehicles in the UK could be affected, with an average of two owners each.

PGMBM managing partner Tom Goodhead said that the case against Mercedes-Benz would highlight how the brand had “abused the trust of its customers”.

A spokeswoman for Mercedes’ parent company, Daimler, told AM: “We believe that the claims are without merit and will vigorously defend against any group action.”