Boris and George, a pair of Chinese characters

If any seeker of tax-reducing write-offs is looking for a British film to back, I believe I have the perfect hearse. The purpose of investing in movies that are virtually guaranteed to fail spectacularly has long been that – for reasons far beyond me – the tax relief massively dwarfs the initial layout. Stick in £100,000, and so long as it does not become an accidental smash in the style of Springtime For Hitler, you get a cool £1 million in relief. Something like that, anyway.

The Chancellor may already have closed this gaping loophole – as I said, my knowledge of the tax system is hardly exact. But if so, he may wish to reopen it and invest some collateral from the wallpaper empire himself, since the movie will largely concern him.

“Boris and George’s Excellent Chinese Adventure” is the working title for an exceedingly minor motion picture dramatising last week’s richly bizarre joint visit by Mr Osborne and the Mayor of London. While it is almost certain that this will be the worst buddy movie since the Dustin Hoffman-Warren Beatty motorway pile-up that was Ishtar, there remains that faint chance that it would be a triumph. It might even emulate the massive success of Rain Man, that other Hoffman road movie, though with the Mayor and the Chancellor it would be in poor taste to speculate as to which is the Tom Cruise pretty boy, and which the one fixated with Abbott and Costello’s “Who’s on first?” routine.

In strictest sooth, both of them looked a little peculiar while making merry in the People’s Republic. The nominal purpose of this trip, planned long ago by Boris and far more recently by George, was to prostrate themselves before the new Chinese Empire, and snaffle some dosh (in the form of loaded Chinese students given visas to spend their renminbi here, and energy firms capable of doing what this country cannot by building nuclear power plants). This they both did splendidly. We may not have seen such elegant sycophancy to a repressive regime by a Western democracy since Donald Rumsfeld went to Baghdad, long after the gassing of the Kurds, to tell Saddam he was a force for modernity and a dear, dear friend – though Mr Tony Blair’s bear-hugging of Colonel Gaddafi will have its fans as well.

Britain and China have not been mates themselves since David Cameron met the Dalai Lama 18 months ago. But even if his old Bullingdon compadres thawed diplomatic relations a smidgen, there was a humiliating end-of-the-pier flavour to their abasement. Once, you felt, watching the uneasy body language as they sat side by side on a university dais, chaps like these were trained to run an empire. When that went, the route to self-abasement was going to America to be patronised in the Oval Office and ignored by the US media. Now, they grovel to the Chinese (not a dickie bird about human rights or Tibet) in the hope of diverting bright 17-year-olds from Apple factories, and inveigling Chinese firms into saving us from the coming energy nightmare of which this week’s price hikes offered a handy hint.

The subtext to this jolly, in which our heroes strove to outshine one another in the twin fields of ingratiation and wit, was wholly domestic. This was so transparently a rehearsal for the next Tory leadership battle that the only surprise was Theresa May’s failure to gatecrash the party, explaining that she somehow mistook a Boeing 777 to Beijing for a black cab from Whitehall. Had she done so, on her colleagues’ showing, she would doubtless have emerged from a guided tour of secret police headquarters to say something admiring about them.

In the absence of Mrs May to play the Katharine Ross eye candy to Boris and George’s Butch and Sundance, the lads had the ring to themselves – though which took a tight split decision is a tough one to call. George looked as puny and uncomfortable as usual (Michael Heseltine, who always managed to look powerful in a hi-vis jacket and hard hat, should tutor him). Boris went that step too far in the quest for laughs by sporting a pudding bowl haircut that would, if administered by a parent in the bath, persuade any judge to grant a child’s application to be declared an emancipated minor.

Curiously, both men did adduce their daughters in the cause of pleasing their hosts. Fresh from an ego-boosting meeting with the No 6 in the Chinese treasury, George threw the first blow by mentioning that his 10-year-old has been teaching him Chinese characters. Boris came back with a haymaker, revealing that his girl is not only learning Mandarin, but will be in China this coming week.

What the Chinese people and media made of their honoured guests is anyone’s guess – mine being very little indeed. Now that China has purchased Africa, the relevance of begging-bowl-carriers from a broke little island with no mineral resources must be minimal. Not, of course, that impressing China was the primary concern of an embryonic double act – potentially the most hilarious since Cannon and Ball, or possibly Burke and Hare – more concerned with electrifying the audience back home.

Whether cinema audiences will be wowed by Boris and George’s Excellent Chinese Adventure, only time will tell. But even with the Oscar-festooned double act of Tom Hanks as the Chancellor and Boris-doppelganger Philip Seymour Hoffman as the Mayor, it looks every inch a banker for the tax dodgers to me.