Car manufacturers including Mercedes-Benz Group AG, Ford Motor Co. and Renault SA are facing a mass class-action style trial after about 1.6 million British car owners claimed compensation for the manipulation of their vehicles to cheat on emission tests.

The high court in London kicked off a three-month trial against five car manufacturers, also including Nissan Motor Co. and a unit of Stellantis NV. All deny they used prohibited “defeat devices.”

The manufacturers decided they would “rather cheat than comply with the law,” Thomas de la Mare, a lawyer for car owners argued on October 13.

The cars didn’t have any prohibited devices, and the claims are flawed and incoherent, lawyers for Mercedes-Benz argued. “The claimants’ case is fundamentally misconceived. It is untenable in law and unsupported by the facts,” lawyers for Renault and Nissan said in court filings. 

The trial, which covers cars made between 2012-2017, is expected to run until March 2026. Following the trial, the judges will decide whether the manufacturers are liable to compensate. A separate trial later will decide the quantum of compensation, if the court rules against the companies. 

The case can result in billions of pounds in liabilities for car manufacturers if the court agrees with the lawyers for car owners. The ruling will also set a precedent for cases against nine other carmakers in the U.K. and similar cases in the Europe. 

“We believe that the claims are without merit and will vigorously defend ourselves against them or any group action with the necessary legal means,” a Mercedes-Benz spokesperson said. 

Stellantis said it firmly believes that its vehicles and engines fully comply with all applicable emission regulations and will strongly defend against these claims, which are unfounded.

Spokespeople for Ford, Nissan and Renault all separately denied the allegations and said their companies will contest the case.

The allegations tied to the original 2015 scandal have cost Volkswagen AG more than $30 billion. 

Volkswagen is not among the five lead defendants in the U.K. trial. The claims are not justified, and Volkswagen will “defend them robustly,” its spokesperson said.

“Fourteen of the biggest car manufacturers operating in the U.K. are facing these claims which, if proven, would demonstrate one of the most egregious breaches of corporate trust in modern times,” according to Leigh Day’s senior partner Martyn Day.