I’m not a great joke-teller. I don’t have the timing for it. But at a wedding on Saturday evening, I got a huge belly laugh from the assembled when I said that some people still believe Stamer will not only win the next election, but will remain in power till the early 2030s. One of my chums nearly choked on his chardonnay. Yes, one or two people really do believe that Starmer will survive that long. But only one or two. Which is staggering when you consider that just a week ago, with Angela Rayner, his main rival, safely disgraced and sent packing to the back benches, Starmer was still sitting pretty.

But, as one of his predecessors, Harold Wilson, famously said, “a week is a long time in politics”. Isn’t it just. Because last week put a bomb under Starmer’s prospects, all thanks to Peter Mandelson and Morgan McSweeney. Suddenly, the thought of Starmer leading Labour till 2029 is simply preposterous. The betting companies now give odds of 13/8 that he’ll be gone as soon as the end of next year.

Some prime ministers, Tory and Labour alike, are simply not up to the job. But none have been more ill-suited than the current incumbent. Starmer got the Labour leadership only because he deceived his far-left members into believing that he’d be “continuity Corbyn”.

And he only became Prime Minister, with his loveless landslide, because, after 14 years, the country was sick to the back teeth of the Tories. Frankly, anyone wearing a red rosette would have triumphed.

Well, the nation is now regretting its decision, and realising Starmer’s government is incapable of improving anything. Smash the gangs? A load of garbage.

Fastest growth in the G7? What a laugh. Improving living standards for “working people”? Stop sniggering at the back. Yes, things were bad under the Tories, who had to contend with Covid and Ukraine, but it’s all now so much worse.

The only thing that could conceivably save the Prime Minister is that the man everyone’s talking up to replace him, Andy Burnham, isn’t an MP. Yet.

And Wes Streeting, the other main contender, has a wafer-thin majority in his constituency. Oh, and Labour’s party rules make it more difficult for them to oust a failing leader than for the Tories.

But none of that will be enough. Sir Keir was already on the steepest of downward slopes before last week, with ratings that make him the least popular prime minister ever after a year in power. Last week exploded any remaining chance he had.

The man is a goner. It’s now a matter of when, not if. And in our modern political age, everything happens much more quickly. Consider this: in early 2020, just after the start of Covid, Boris Johnson was polling in the high 50s. Two years later, he was out.

If a week is a long time in politics, what’s eight months? Because eight months from now, we’ll see a massive electoral test for the Prime Minister – the May local elections, as well as the elections for the Welsh and Scottish Parliaments.

Unless something dramatically favourable for Sir Keir happens before then – and I can’t imagine what – Labour will be decimated and Reform triumphant. And, if it hasn’t already happened, that’s when the men in grey suits will go up to him and tell him it’s game over.

Starmer’s been lucky with his enemies so far. And lucky with his timing. But no prime minister can survive for long on luck alone. If I were Andy Burnham or Wes Streeting, I’d be licking my lips.