German luxury car maker BMW said on Monday it would invest an extra 250 million pounds (300 million euros, $387 million) in its Mini brand over the next three years, marking a boost for the 5,500 workers. The investment would mainly benefit BMW\'s manufacturing centre in Oxford, southern England, as well as factories in nearby Swindon and an engine plant near Birmingham in central England, the German firm said. This \"comes on top of the 500 million pound investment announced in June 2011 and means additional job security for the 5,500 UK associates working in the ... plants,\" said BMW in a statement. Harald Krueger, a BMW board member, said BMW\'s total investment in Britain since 2000 had amounted to 1.75 billion pounds. He added that Britain was a \"vital manufacturing base\" for BMW and stressed the firm\'s commitment to the Oxford plant. \"Just as Munich is the centre of the BMW world, Oxford is and will remain the home and the heart of Mini,\" he said. Cars from the Oxford plant are exported to more than 100 countries, BMW said.