Citizenship is one thing that is never supposed to depend on how much money you have. The sheer luck of birth and "blood" is supposed to determine what rights and privileges you have, where you can travel. But wherever blood flows, money follows.

In Britain, citizenship can increasingly be bought, or at least priced. This is a matter of government policy. Some of this can be traced back to a promise that David Cameron made back in 2010 to reduce net migration to no more than 100,000 a year. It was an arbitrary, pointless and, more importantly, completely unworkable figure. But the government had to somehow make it happen, despite knowing that it could do nothing about European Union migration.

Ultimately, Cameron's inability to deliver a cap on migration from the EU consolidated the right-wing consensus for Brexit. But in the meantime, he was able to crack down on non-EU migration in a number of ways.

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First, in an effort to curb the movement of poor migrants from outside the European Economic Area, introduced a minimum income threshold for non-European spouses of British citizens of $23,100.

Last week, this law was upheld by the Supreme Court, despite its cruelties and arbitrariness. In addition, as of April 6 last year, non-EU migrants who want to settle permanently in the UK must have an income of at least $43,500.

Contrast the migrants affected by this, with those for whom the government rolls out the red carpet.

In Britain's multitiered visa system, there are now many routes to citizenship (PDF). For those prepared to invest $1.24m in companies registered in Britain, there is Tier 1: a fast-tracked visa system and a lubricated route to full citizenship. Once in Britain, they will also have access to "non-domicile" tax status, meaning that while they live in the UK, for taxation purposes they will be considered to live elsewhere - for example in the Cayman Islands.

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Increasingly, moreover, this exceptional tax regime for migrant capitalists is one that Britain seems to be prizing as a post-Brexit comparative advantage.

The EU committee investigating the Panama Papers and tax havens has described the UK as being "on its way to a prime tax haven". The strategy is to welcome people with money, let them keep as much of it as possible, and wait for them to invest, usually in government bonds.

This is incredibly short-sighted. Keeping out skilled workers isn't good for employers. Yet, that is what the laws have achieved. The Migration Observatory, based at the University of Oxford, found that skilled migration from non-EU countries had plummeted by a third after the changes were implemented.

A global pattern

Attracting more oligarchs and tax evaders to the capital does nothing for the economy in the long run. It leads to little productive investment, nor does it answer any particular shortage. Government bonds are never difficult to sell.

All it does is drive up property prices around London, and contribute to the financial bubble. But the golden rule of modern migration politics is that the super-rich are footloose and fancy-free, while the poor have to be rooted to the spot, no matter how desolate.

Anti-immigrant sentiment has always had a class content. It has been the poor, or those stereotyped for having the supposed attributes of the poor - criminality, vulgarity, disease, lack of cleanliness - who have been targeted.

This is part of a global pattern, wherein national and racial exclusions are intersecting with class distinctions. While immigration laws penalise the poor, the rich have always found a way round closed borders and quotas.

Now, there is a growing class of "economic citizens", comprised rich investors buying passports. A range of tiny states offer "citizenship-by-investment" so that, for example, a Russian oligarch can have an EU passport from Cyprus for $2.1m. Citizenship is one of the last global frontiers of commodification.

The surprisingly sanguine attitude to this can be contrasted with febrile reporting about Moldovans. The Sun has described residents of Moldova as "flooding" into the UK.

German and French press are filled with scare stories alleging that Moldovans are illegitimately obtaining Romanian passports in order to become EU citizens.

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The process by which Moldovans acquire a Romanian passport is that they dig up old Soviet-era documents proving that a grandfather or great uncle was Romanian. They then submit to a lengthy and labyrinthine application process and after two years, they might get a passport.

Where it gets interesting, is where principles of bloodlines and money suddenly intersect. Moldovan migrants have been blamed for adulterating the integrity of bloodlines by making spurious claims to Romanian blood, thus undermining the whole EU passport system. But then, they didn't bring investment cash.

For those who can pay to override the bloodline principle, all objections suddenly become irrelevant. Even the idea floated by Guy Verhofstadt, the European Parliament's top Brexit negotiator that post-Brexit Britons could buy "associate citizenship" of the EU was more scoffed at by opponents than it was a source of anger.

Commodification of citizenship

The logic of commodification of citizenship is only in its very early stages, yet already it can override the principle of birthright. Does this tell us something about the shape of 21st-century capitalism? As much as capitalism has internationalised, it has always needed the national state.

But patterns of investment and work in the future will demand more migration. Citizens will become less rooted to the town, county and nation of their birth. Immigrants, far from being an alien minority who can be "kept out", are all of us. We are all immigrants in the hereafter.

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Anti-immigrant sentiment has always had a class content. It has been the poor, or those stereotyped for having the supposed attributes of the poor - criminality, vulgarity, disease, lack of cleanliness - who have been targeted. When Nigel Farage attacked the poorer "quality" of Eastern European migrants, this is what he had in mind.

And since we are the migrants of the future, it should alarm us that the means by which new, more mobile forms of citizenship are being allocated, are markets and prices. Because that means the world is becoming a playground for the rich from which we, the majority, are banned.

Richard Seymour is an author and broadcaster based in London. He has written for The Guardian, the London Review of Books and many other publications.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.