Something remarkable happened this week. Labour’s Sir Keir Starmer, the leader of the opposition, made several decent jokes in the House of Commons. Up against a beleaguered Boris Johnson, Starmer looked for the first time in these encounters as though he was enjoying himself. At one point he said with a smile that at least the Number 10 team knows how to pack a suitcase, a reference to the potential departure of the Prime Minister and the “wine suitcase” Downing Street staffers wheeled to the supermarket and filled with booze for their illicit parties.