US President Donald Trump on Sunday backed British Prime Minister Boris Johnson as the “right man” for Brexit and sent mixed signals about his trade war with China at a G7 summit dominated by worries about the global economy. Johnson and Trump were on obviously friendly terms as they sat down for a working breakfast in the southern French resort of Biarritz where Group of Seven leaders are gathering this weekend. “He’s going to be a fantastic prime minister,” Trump said in their first meeting since Johnson took office last month.