David Bodanis: Fusion of talent in the City is the right recipe for success

Midweek View: London's diversity is greatly impressive now, but doomed to collapse probably within a generation

What will happen to the City of London if the new Obama administration – as seems likely – makes it easier for educated immigrants to work in the United States?

London has a strength that hardly any other cities do. It's not just the English language, or its unbribable judges, or the legacy of Empire. Those are fine, but in addition London has an odd sort of diversity: greatly impressive now, but doomed to collapse probably within a generation, independent of what America does.

Let me explain. When there's too little mixing in a city, you don't get a chance to learn from others. Frankfurt is very German, Paris is very French – and that does not stimulate massive creativity. As Percy Barnevik, the long-time head of the Swedish-Swiss group ABB, put it, you can't have a successful board composed entirely of Swedish men talking about moose.

Although London too has German bankers, and French mathematicians – and no doubt even a good number of Swedish financiers, easily excited when thinking about naked moose – it also has financially astute citizens of seemingly every nation on earth, as a Friday evening strolling past any of the pubs on the outskirts of Liverpool Street shows.

That itself is good, but a vast range of nationalities on its own still isn't enough to spark creativity. Much of the American Midwest has people who came from many different countries, but they've largely become homogenised.

A closer listen-in to those conversations in Liverpool Street or Shoreditch shows it's different here. The multiple nationalities in London are often dressed similarly enough – and are most happy, in their early evening flirting, to go home with whoever responds – but they still, very much, carry different styles. The French quants know they should look bored, and the California women know they should talk loudly, and the …

Well, it's the intermediate zone astrophysicists have spent billions of dollars hunting the heavens for. Too far from a star, and a new planet is too ice-ridden for life. That's Frankfurt. Yet orbit too close to a star, and everything on a planet has melted to a uniform protoplasmic goo. That's our Midwestern shopping malls.

But in-between, when everything's just right? Then there can be wondrously diverse life: sharing enough similarity that everyone can interact, but not so much that everyone operates in lock-step.

There's even a benefit from the rest of the world being less diverse. France's grandes écoles are superb, but hire far fewer non-native professors than, say, Imperial or MIT do. This means Paris's Polytéchnique has had the space to develop a distinctive mathematical style.

Its students will learn that style, but if they get frustrated by Paris's formality and old-boys networks, they'll waft like dandelion seeds across the Channel, drawn by visions of cash, of no old-boys networks (and perhaps even by those very, very un-French California women). Similarly for South African accountants, graduates of India's Institutes of Technology, and all the rest. All bring the distinctive training they had at home.

Will it last? To some extent the diversity will naturally come to an end as hormones take their course, and new families form, settled in London, where although the children might pick up a smattering of foreign words from their parents, their attitudes will be British 100 per cent.

This is the failure of all arbitrage: wonderful opportunities arise, but as soon as they're taken up, the original opportunities disappear.

We see this already happening in restaurants. Just a half generation ago, someone like Ken Hom could excite people by suggesting that Italian basil would be unutterably exciting if mixed with Chinese soy sauce. Now, fusion restaurants have to stretch ever further afield to get a chance of standing out.

Let's make that our litmus test; our canary in the mines. At the moment a restaurant like Hakkasan captures our city's diverse mix to perfection. But if Hakkasan ever goes too far – if we ever start finding vindaloo ceviche, or gravadlax tacos there – then we'll know it really is time to short Hoxton prices, pack up, and start afresh in the land of Mr Bloomberg and yellow cabs.

So long, that is, as enough diversely educated travelling companions are allowed.

David Bodanis is a consultant on innovation and the future of financial trading. His 'History of the Ten Commandments' is published by Bloomsbury next year