Most were making the trip for the first time in years to refresh their partnership with the world's second-largest economy. Vietnam and the European Union also on Thursday committed to deeper cooperation on trade, technology and security. "Half of economic growth is generated by either the United States or China," Lee-Makiyama said, adding that "the United States is hardly opening up". - 'No longer reliable' -Trump's unpredictable tariff onslaught signals that "the United States is no longer a reliable trading partner", said William Alan Reinsch at the Washington-based Center for Strategic and International Studies. Nonetheless, China remains Britain's third-largest trading partner, and Starmer's centre-left government is keen to boost UK economic growth.