For his last trick, the king revealed a bell that hung from the conning tower of a Royal Navy submarine launched from a UK shipyard in 1944. Its name was HMS Trump. “And should you ever need to get hold of us,” Charles III said , “well, just give us a ring.” The polished brass bell bearing the name “Trump”, presented at Tuesday’s state dinner at the White House, was an ego-flattering masterstroke that will have prompted groans in foreign capitals from Paris to Canberra to Tokyo. How can they ever hope to match that? But for all the gushing praise on both sides of the Atlantic for Charles’s elegant display of diplomacy on his visit to the US this week, British prime minister Keir Starmer would do well to remember the problem with soft power is it is soft, and can quickly scatter like blossom on the wind. Donald Trump is notorious for blowing hot and cold: while the monarch bathed in the warmth of his anglophilia, citizen Starmer can still expect the cold shoulder. This was a trip laced with ironies.…