New research from the Tax Justice Network – an organisation devoted to making the rich pony up their due - says that a minimum of $21trn is held offshore. This stash should worry us all.

This is not just because it is money which could generate $190bn in taxes to be spent by governments on, say, paying down debt, building schools or hiring nurses. What is as important is the effect this hidden money has on social inequality.

Alongside the report with the $21trn figure (which may in fact be $32trn, or somewhere in between, or indeed less), the TJN published "Inequality: You don't know the half of it", which hews to the argument of The Spirit Level and similar texts, that inequality increases social problems, and shows how it is now a much greater problem in the light of its new research:

"Power follows money, and extreme concentrations of wealth at the top of the income scale lead inevitably to disproportionate power and influence for the wealthiest members of society, so some of the most malign political effects of inequality stem from changes as the very top of the income and wealth distribution."

The British government is certainly making some efforts to tackle tax avoidance - all those Carr-ish schemes are being stopped - but it's with one eye closed. As Nicholas Shaxson pointed out in his book Treasure Islands: Tax havens and the men who stole the world, the fons et origo of tax havens is… London. With New York, "the jurisdictions act as capitals of secret empires, exploiting their hand-in-glove relationships with former colonies to tap funds that would otherwise be deemed too dirty to handle."

If the government can't make the connection between the money that flows into the City from tax havens and the riots on London's streets, it should perhaps pay attention to the Tax Justice Network, crusaders even without capes.

Josh Spero is the editor of Spear's.