Tesla’s boss, Elon Musk, once thought the idea that China’s BYD could compete with his company was laughable. In 2011, he smugly dismissed the Chinese carmaker as unimpressive, its products unattractive and its technology “not very strong”. He’s not laughing now – and not just because Tesla’s stock has plummeted amid a boycott by motorists protesting against his embrace of far-right politics. More pressingly, Mr Musk, like other western carmakers, has been outpaced by BYD. Last week, the Chinese electric vehicle (EV) manufacturer unveiled new charging technology that, it says, is capable of delivering 400km (249 miles) of driving range…