The U.S. electric car company’s sales are sliding across Europe, amid what many see as interference in local affairs by Tesla’s chief executive, Elon Musk.

Musk, who also runs SpaceX and a number of other companies, has been known to make big often exaggerated promises. For example, he once called the Hyperloop, which was never built, the "fifth mode of transport" and famously promised to take Tesla private in a Twitter post, saying he had secured financing that he didn't have.