Donald Trump is reportedly still threatening to block Peter Mandelson’s appointment as Britain’s next ambassador to Washington, unless the UK government agrees to impose tight restrictions on his conduct. The incoming Trump administration is said to be pressuring Sir Keir Starmer to bow to these “undiplomatic” demands or risk an unprecedented refusal of his chosen envoy. A source close to the Trump team claimed the president remains determined to reject Lord Mandelson’s credentials but might...