I remember a really good article on optimum city size theory and can't find it now. Had good clear graphics to show that a capital should (according to the theory) have 3 or 4 smaller cities of about 50% of its size, and then another 7 or 8 of 50% again etc. Most (?) developed countries sort of manage this but the UK is significantly out of kilter.
Anyway, I found this article instead
The finance curse: how the outsized power of the City of London makes Britain poorer
Some key bits (for me):
''A growing body of economic research confirms that once a financial sector grows above an optimal size and beyond its useful roles, it begins to harm the country that hosts it. The most obvious source of damage comes in the form of financial crises – including the one we are still recovering from a decade after the fact. But the problem is in fact older, and bigger. Long ago, our oversized financial sector began turning away from supporting the creation of wealth, and towards extracting it from other parts of the economy. To achieve this, it shapes laws, rules, thinktanks and even our culture so that they support it. The outcomes include lower economic growth, steeper inequality, distorted markets, spreading crime, deeper corruption, the hollowing-out of alternative economic sectors and more."
And this
"Or, consider the financial structure of Trainline, the online rail ticket seller. When you buy a ticket, you may pay a small booking fee, perhaps 75p. After leaving your bank account, that 75p takes an extraordinary financial journey. It starts with London-based Trainline.com Limited, then flows up to another company that owns the first, called Trainline Holdings Limited. That company is owned by another, which is owned by another and so on.
Five companies up and your brave little 75p skips off to the tax haven of Jersey, then back again to London, where it passes through five more companies, then back to Jersey, then over to Luxembourg, another tax haven. Higher up still, it passes through three or more impenetrable companies in the Cayman Islands, then joins a multitude of other rivulets and streams entering the US, where, 20 or so companies after starting, it flows to KKR, a giant US investment firm.
It flows onwards, to KKR’s shareholders, including banks, investment funds and billionaires. KKR owns or part-owns more than 180 real, solid companies including the car-sharing firm Lyft, Sonos audio systems and Trainline. But on top of those 180 real firms, KKR has at least 4,000 corporate entities, including more than 800 in the Cayman Islands, links in snaking chains of entities with peculiar names drawn from finance’s arcane lingo, like (in Trainline’s case) Trainline Junior Mezz Limited or Victoria Investments Intermediate Holdco Limited."
www.theguardian.com/news/2018/oct/05/the-finance-curse-how-the-outsized-power-of-the-city-of-london-makes-britain-poorer