The public has agreed that the thing Keir Starmer had to resign for in February, but did not and which was soon forgotten, must be resigned for again.

Further details about the appointment of Peter Mandelson, for which the prime minister already had no choice but to leave office in disgrace but unaccountably did not, mean he definitely has to go this time.

Westminster insider Denys Finch Hatton said: “Why on earth is Starmer saying he’s not going to resign? Does he imagine it’s his decision?

“Like King Canute commanding the tide, like Trump ordering an Israeli ceasefire, Starmer’s pathetic attempts to defy reality are doomed. This is career-ending. It was two months ago and it’s no less true now.

“The leaders of all other parties are calling for it, for God’s sake. These aren’t desperate opportunists trying to capitalize on anything that makes headlines. Kemi Badenoch, Nigel Farage; these are politicians of integrity.

“No, there’s no one in Labour calling for it whose word carries the same weight as that Scottish bloke. But we think we can get Carol Vorderman by mid-afternoon. Will she do?”

The Mandelson affair is expected to now be forgotten until after the May council elections, when Starmer will have to resign for it again.