If things were going well at home, no one would object to the prime minister’s foreign trips, says John Rentoul I t seemed a long way to go just to take Iain Duncan Smith ’s proudest boast away from him. Keir Starmer flew thousands of miles to the court of Xi Jinping to boast about a cut in China’s tariff on Scottish whisky and the unbanning of the Conservatives’ former leader . Duncan Smith and seven other British parliamentarians were sanctioned by the Chinese government five years ago for