David Lammy was never a politician to mince his words. He has previously described Brexit as a “national tragedy”, Donald Trump as a “tyrant in a toupee” and called out Italy’s deputy prime minister for “old-school racism”. But in more recent times, in particular since he took over as foreign secretary last year, Lammy has faced multiple tests of his diplomatic skills. None more so than having to carefully craft the UK response to the slew of contentious announcements now coming out of the White House. The new US president has threatened to withdraw military support from Ukraine, announced trade...