In cosying up to Cameron so soon after an odious anti-Muslim Tory campaign, Sadiq Khan disappointed us all

What Khan was really doing by so overtly relishing this ego-massaging love-in was tacitly suggesting that race-baiting is nothing to fret about so long as it’s spouted during a campaign. He owed it to young Muslims everywhere not to forget so quickly

Sadiq Khan and David Cameron at Remain rally in south London yesterday (EPA)

In politics, much like elsewhere but only more so, relationships are in a constant state of flux.

In 1984, 15 months after the Dujail Massacre for which the tyrant was later nominally hanged, Donald Rumsfeld appeared on the front page of the Baghdad Gazette shaking Saddam’s hand and praising him as a regional force for modernity. Sadly, as you recall, that friendship did not endure.

For more than a decade, meanwhile, Gordon Brown and Peter Mandelson nurtured a psychotic reciprocal hatred – until the moment Brown needed Mandy to survive, and recalled him from Brussels to run the government on his behalf.

With that absurd moment branded forever on the memory, no political allegiance should have the power to shock. But however high one’s tolerance level for the marriage of convenience, however blunted the tastebuds to the acidic flavour of rank opportunism, the defences were pierced on Monday when London’s Mayor and the Prime Minister launched themselves as a cross-party Remain double act.

Where years of transition are usually required for enmity to morph into a friendship, it was as recently as April that David Cameron smeared Sadiq Khan by association, at PMQs, as a sympathiser with Islamic extremists. “It is very important we do not back these people and do not appear on platforms with these people,” he said. “I have to say I am concerned about Labour’s candidate for Mayor of London who has appeared again and again and again.”

How quickly that genuine concern faded into equally sincere admiration. In the Prime Minister’s infinitely supple mind, April’s terrorism fellow traveller is reborn in May as a “proud Muslim, a proud Briton” with whom he is proud to share a platform in the cause of keeping us in the EU. It’s a miracle, it’s a miracle!

Which of these two most deserves the metaphorical hiding for this joint appearance is less clear cut than one might assume. On first watching the footage, it is Cameron who clearly merits the slap. Within 50 days of sketching Khan as the Trojan Horse of Islamic extremism, he heaped honeyed words on his head with no hint of apology or even explanation for that previous depiction.

When the new Mayor tried a spot of self-parody, asking the crowd if it was aware of his father’s career, the PM chortled as if listening to Algonquin Round Table’s Greatest Hits on a hidden earpiece while being force-fed newly illegal nitrous oxide and having the soles of his feet tickled. Had Khan recited the timetable from his old man’s No 44 bus route, he would likely have yielded bodily function control. “11.26 Petergate. 11.30 Swandon Road. 11.33 Wandsworth Town Station …” “Oh, do stop,” Cameron would have whimpered in an echo of Brian Johnston’s Test Match Special giggling fit. “Sadiquers, for heaven’s sake… ”

As for Cameron’s claim that being a stockbroker’s son is “less romantic” than being that of a bus driver, we’ll let that magisterially condescending idea pass to ask what Sadiq Khan was doing there. While it was one thing to share a platform with Cameron, to share it without any direct reference to the disgusting Tory mayoral campaign the PM so merrily endorsed was another. I’m a stickler for good manners, but this was politeness gone mad.

What Khan thought he was doing, we might guess, was studiously playing the high-minded statesman, nobly suppressing any personal feelings in the interests of a higher cause. The true intent, we may also guess, was to bolster his embryonic credentials to succeed Jeremy Corbyn (with whom he is far less keen to share a platform, though that might well change if and when Corbo smears him as a suicide bomber manqué).

What Khan was really doing by so overtly relishing this ego-massaging love-in was tacitly suggesting that race-baiting is nothing to fret about so long as it’s spouted during a campaign; that this kind of stuff – spouting vicious falsehoods they don’t believe for short term tactical gain – is just what politicians do. If such stuff happens subliminally to endorse the deranged myth that most Muslims support terrorism, if it inflames false suspicion and plays straight into the hands of active racists, so be it. It’s all a big game. Even if they kicked lumps out of each other on the park, once the final whistle blows, the rivals shake hands and head off for a pint, and sod the collateral damage.

There is plenty to like about Khan beyond the pure joy of having seen a Muslim win a prestigious election in defiance of such an odious Tory campaign. But on behalf of all victims of vicious anti-Muslim sentiment – whether himself or a young Asian teen being chased down a Bradford alley by morons screaming “Paki” – he had a responsibility to avoid such a smugly amnesiac show of pleasure at the grandeur of the company he now keeps.

On the basis that Cameron long since exhausted his capacity to surprise with the range and glibness of his hypocrisy, it is not the PM but Khan whose presence on Monday was the more disappointing. If his intention was to present himself as a freshly minted, post-New Labour political leader, the naked cynicism of this foolish alliance achieved precisely the opposite result.