Brussels is open to developing a powerful new trade weapon that could contain a kill switch that would quickly eject Chinese companies from the EU market, the bloc’s national leaders were told during a top level meeting in the Belgian capital on Thursday. There was broad support among the 27 members for such a tool, first laid out in a French-German joint paper last week, with European Commission President Ursula von der Leyen signalling that her trade team could get to work on developing it,...