Everyone agrees the world needs greener cars and Wang Chuanfu believes he is the man to deliver them – by combining Chinese brains and hard work with Warren Buffett’s money.

Just over a month ago – when the Dow Jones index fell nearly 7 per cent, one of Wall Street’s worst days – Mr Buffett’s Mid­American Energy Holdings bought a 10 per cent stake in BYD, the company that Mr Wang founded.