Downing Street has rung me before when previous tenants appeared on the threshold of the last chance saloon: Boris Johnson and Liz Truss.
This was Sir Keir feeling the necessity to take on the claim by the now former Defence Secretary John Healey that the country’s national security could be imperilled unless much more was spent on defence.
He pointedly said every cabinet minister, every government department, had contributed cuts to their long-term, so-called capital budgets, to provide more for defence. The prime minister himself was involved in plenty of these negotiations, I’m told – and some were pretty hard going, given it required reopening budget deals that had been assumed to have been already settled.
The question for some is whether that was ever likely to be a sufficient mechanism for generating enough money.
The Conservatives, Reform UK, as well as some of those wanting Sir Keir to succeed, such as the former Labour defence secretary and former Secretary General of Nato Lord Robertson, have said the focus instead should be on cutting the rapidly rising benefits bill.
Sir Keir said he did hope that within the coming years that bill could come down.