It still feels improbable that the British prime minister, Keir Starmer, will face a formal challenge even if, as assumed, his Labour party performs disastrously in next month’s local elections. But for many of his MPs, the latest revelations about Peter Mandelson have emphasised that the question is simply one of when, not if.
“It does seems incredible that he didn’t know, but the problem is that it’s quite possible as well,” was the summary of one backbencher, in response to No 10’s insistence that no one had told the prime minister that his pick to be the UK’s ambassador to Washington had failed his security vetting.