. . Any final exit of Britain from the European Union that exacerbates business conditions by increasing tariffs would threaten the sustainability of Nissan Motor Co. UK operations, the Japanese carmaker's chief operating officer warned. Nissan, which employs 7,000 people at Britain's largest auto plant in the northeastern city of Sunderland, in June called for a "structured and balanced Brexit". "If this happens without any sustainable business case, it is clearly not an issue of Sunderland or not Sunderland, it is clear that our UK business is not going to be sustainable, that's it," Nissan's chief operating officer Ashwani Gupta told Reuters on Wednesday.. ".