WOLFSBURG—Beleaguered automaker Volkswagen has called on a quartet of PR firms to oversee its global crisis PR response as it attempts to deal with the biggest scandal in its 78-year history, the Holmes Report can reveal.

The Holmes Report understands that Volkswagen has brought in German firm Hering Schuppener as lead PR counsel, supported by Finsbury in London and Kekst in the US. In addition, Edelman is helping the automaker handle US consumer PR outreach, as part of its existing relationship with the company.

The crisis erupted last week when Volkswagen admitted it distorted emissions tests results in order to pass US environmental requirements. More than 11m diesel cars had 'defeat device' software installed that manipulated test results, despite warnings, leading chief executive Martin Winterkorn to step down last week.

The company has since named Matthias Müller as its new CEO and said there is "no excuse for the manipulations". It has pledged to leave "no stone unturned" in resolving the scandal, beginning with legal investigations in Germany and the US. As many as 11m Volkswagen cars are set to be recalled, with Müller describing the situation as the "severest test in its history", according to a Reuters report.

"The test manipulations are a moral and political disaster for Volkswagen," said Volkswagen deputy chairman Berthold Huber in the statement. "The unlawful behavior of engineers and technicians involved in engine development shocked Volkswagen just as much as it shocked the public."

An observer familiar with the situation noted that the stakes could not be higher. "This is not just a crisis of a major industrial firm. It’s gone way beyond that, it could affect the German economy."

Representatives from Hering Schuppener declined to comment, while Volkswagen did not respond to request for comment as this story went live.