UK Prime Minister Keir Starmer arrived in the Chinese financial centre of Shanghai on Friday in his bid to boost business opportunities for British firms in the world’s second-largest economy, just hours after US President Donald Trump signalled a possible opposition to any deal between Beijing and London.Starmer, the centre-left Labour leader, has brought more than 50 business leaders on his trip to China, the first by a UK prime minister in eight years. He started his trip in Beijing, where he met with Chinese leaders including Xi Jinping.In Washington, Trump suggested that he may oppose any deal, and then pivoted to Canada, with which he has had a series of sharp exchanges since Canadian Prime Minister Mark Carney visited China earlier this month.Tariff threat to CanadaPresident Donald Trump said on Thursday the US was decertifying Bombardier Global Express business jets and threatened 50% import tariffs on all aircraft made in Canada until the country’s regulator certified a number of planes produced by US rival Gulfstream.