In a sea of Trump-a-likes, Sadiq Khan is starting to look like our prime minister in waiting

He's the only one with the guts to stand up to the US president – and to have emerged untarnished from this Brexit mess

At today’s Downing Street lunch, I read, the pudding will be Eton Mess. Hats off to the No 10 catering manager for the ironic wit. We’ve been dining exclusively on the Eton mess bequeathed us by David Cameron for three years.

If the Tory leadership favourite lands the odds, we’ll be force fed more for a while to come. The entire country is quagmired in an Eton mess. It still isn’t known whether President Donald J Bonespurs, joining us in his official role as Draft Dodger-In-Chief to mark D Day’s 75th anniversary, will anoint Boris Johnson as his chosen successor to Theresa May in person.

But while the erstwhile London Mayor distracts himself from the anxious wait for an audience, it is the incumbent who has stolen the show. If Sadiq Khan’s re-election next year looked likely before his latest spat with the creature from the orange lagoon, it is guaranteed after it – assuming he isn’t diverted towards an even larger job. The current Labour leader, meanwhile, is off to Trafalgar Square to address an anti-Trump demo. Like Trump, Jeremy Corbyn is only fully at ease preaching old sermons to the choir.

So he’ll be trotting out some moth-eaten reflections about Trump’s misogyny. To do so, he’s bunking off a PLP meeting where the cover up of a member of staff’s abuse of women would have shared the agenda with the European elections disaster. Purest Trump, whose reflex response to intense pressure is to take Air Force One to a redneck citadel and whip up the faithful with "Lock Her Up" and "America First".

Whether Corbyn should be skipping banquets and his own MPs in favour of student politicking is hard to call. If the next Eton mess, or whoever, is forced to call an election, he could be in No 10 within months. In that event, the realpolitik will impinge. A prime minister can’t avoid meeting other leaders, however visceral the distaste, or call them "twats". We don’t live inside a Richard Curtis script. A PM-in-waiting, possibly on the verge of power, ought to understand that. In other contexts, Corbyn does.

He cites the need to engage and talk (even to honour them as “friends”) when attacked for associating with some unlovely folk. But a potential prime minister with the luxury of playing the long game can do as they please – and Khan pleased more than himself with a two-pronged take down of the abomination in an article and a video message.

Where Trump diminished Corbyn by ignoring him, he elevated Khan by reacting to “20th century fascist”. He not only tweeted “stone cold loser” and “foolishly nasty”, which gives Khan the edge over Corbyn’s fellow banquet-boycotter Meghan, Duchess of Sussex, who is just “nasty”. Like a tearful infant on an outing to the seaside, he whined to Jeremy Hunt about having the sand kicked in his face.Hunt took a dim view about Khan’s impertinence, which he found beneath his dignity “when I as foreign secretary am trying to bring peace to Yemen.” And which resident of 1600 Pennsylvania Avenue does Hunt imagine vetoed a Congressional ban on selling arms to the Saudis to enable them to continue making war in Yemen?

Hunt’s latest foray into the wasteland of cultivated imbecility came as a reminder that, however grotesque in itself, the state visit is beautifully timed. This leadership race is an unusually dismal series of The Apprentice masquerading as high stakes combat politics. We all know who the terracotta grifter would hire for being the closest reflection to himself. But Nigel Farage isn’t in the game, at least for now.

The sloppy pudding from the school within a bread roll’s throw of Windsor Castle, the PG Wodehouse version of Trump, who made merry in print about “picanninies” with their “watermelon smiles”, will suffice as second choice. He obviously reckons Boris would make a loyal and enthusiastic executive, on a rung just above Sarah Sanders and a few below Jared Kushner and Ivanka Trump; that he’d wolf down the chlorinated chicken for the cameras and open the NHS gates to an American big pharma stampede. And he’s probably right.

Under this and any president who follows, resisting the bullying that’s defined the special relationship since FDR sent a gunboat to Cape Town to collect British gold would be as difficult for an impoverished, impotent post-Brexit Britain as it would be essential. It wouldn’t be considered an option by any of the would-be apprentices on view (with the possible exception of Rory Stewart, an interesting candidate but a no hoper). It wouldn’t be achieved by choosing to grandstand at demos over talking, and cementing the isolation.

Is there anyone in British politics with the balls and brains, the ideals and the pragmatism, to navigate the minefield ahead. Or, better still, to avoid it?

Probably not. But the more you gaze in stupefied horror at the leadership of the two main parties, the more you recoil in terror from the rise of mini-Trumps in and outside the Commons, the better Sadiq Khan looks.

After penetrating Trump’s skin with such elegant ease, there is only one reason why he won’t replicate the "Eton mess" by serving two terms as London mayor. With the hard left controlling Labour’s levers of power, the logistics of doing a Boris and getting back to the Commons are troublesome.

Corbyn is at a moment of maximum vulnerability, and the centre left is screaming for a leader. If he wants a crack at it, he needs to move right now.