Lotus is planning to end production of its sportscars in the UK and shift it to the US, a move that would put 1,300 jobs at risk and represent a major blow to the British car industry. The carmaker’s Chinese owner, Geely, is looking at options including manufacturing its Emira sportscar in the US, and permanently stopping production at its factory in Hethel, Norfolk, according to a person with knowledge of the company’s thinking. No final decision has been made. Workers at the factory, in a former second world war…