Not trying to contradict your argument, but I was thinking the same... What does UK produce uniquely, and so far I have come up with airplane engines.
Plenty of sources, but first ones to come were "Global Top 4 Aircraft Engine Manufacturers - Strategic Factor Analysis Summary (SFAS) Framework Analysis - 2015 Pratt & Whitney, GE Aviation, Rolls-Royce, Safran".
Don't get me wrong, Uk is top notch there with Rolls Royce, and they're not a manufacturer aircraft maker would want to ignore being for price nor performance, but it's not something we would lose or need to rebuild if the UK were to suddenly fall into a vortex or something.
As for the article, speaking as someone from the UK, as far as I'm concerned the UK did a deal with the devil back in the 80s, focusing on the fake prosperity of the financial services industry (gambling on markets is ultimately a waste of effort) in place of growth in the productive economy (manufacturing industries were neglected for decades). If Brexit means the government is forced to diversify and not rely so heavily on financial services it could be a very good thing for the UK. There will certainly be challenges in changing the economy if we leave the European single market (I can't see hard Brexit happening anyway, there's very likely to be some form of compromise), but I'll not be crying over lost banker jobs, they can be someone else's problem now.
I think it's sad that people with a PhDs in physics/mathematics seem more likely to end up spending his/her time optimizing my car insurance premium than solving real problems.
It's all good and fun to say bankers jobs will be somebody else's problem, but you are offering to replace that money with what, exactly ?
The UK used to be the laughing stock and sick man of Europe in the late 70s, had IMF loans like Greece today. It really doesn't take that much more than a wound like Brexit to fall back again into misery over a couple of decades.
But that's the problem, over-reliance on a single industry.
The thing is, it wasn't seen as a weakness by politicians whilst the money was rolling in. However, many people outside London recognised it as a weakness as their industries were being neglected whilst the UK transitioned towards becoming a service economy.
I'm not suggesting their won't be a downturn from bankers leaving, but I am suggesting it's a necessary one to break the myth that the service economy approach is the only one worth pursuing. The UK will need to become more self-reliant to return to stability, and that will ultimately be a good thing.
ARM is owned by SoftBank, for what it's worth.