This month, while reporting in Athens, I saw a young Pakistani man get his head split open by the sort of street fascists whose anti-immigrant rhetoric has been echoing around Europe for years. The Greek Golden Dawn Party has its equivalents across the Continent, including in Britain, and it is into this climate of violent hostility towards migrants and foreigners that the Olympic Games, a notional celebration of team spirit across borders, is arriving.

In these anxious times, international solidarity only goes so far. There is political capital to be made by exploiting knee-jerk hostility towards immigrants, and as the world's greatest athletes and their supporters arrive on British soil, preparations are already under way to make sure that each and every one of them goes home when the Olympics are over. Ten years ago, when Manchester hosted the Commonwealth Games, almost the entire Sierra Leonian athletics team failed to show up at the airport for the return journey – most are, one hopes, living happily somewhere in Britain, safe in the knowledge that immigration officials can't outrun them.

This time, though, Britain is prepared. The borders, like the whole of east London, are on lock-down. As a demonstration of just how committed the Home Office is to running a Games whose immigration checks at least are watertight, members of the Olympic "family" – officials, athletes and their entourage – will not be permitted to marry while they're in Britain. This, presumably, is designed to forestall the possibility of visa-related romance spoiling any official fun that may or may not be being had behind the ring of steel. Just what sort of international spirit are we supposed to be celebrating here?

The Games have always been about far more than sport. I don't want to bitch and whine about the Olympics, even though bitching and whining about the Olympics is probably the one international sport in which Britain would be assured a gold medal. Fundamentally, a symbolic truce every four years for a bit of healthy, non-lethal inter-country competition is a good idea. The Games are supposed to showcase a spirit of internationalism and foster a sense of community that crosses borders. The important questions here are: what kind of community, and what kind of borders?

The accreditation process for the Games is forensic, and competitors and spectators will be scanned, searched, filmed and watched from the day they arrive at Heathrow until the moment of departure – nobody wants another 2002 Commonwealth Games. They will all, in addition, have to abide by a strict code of dress and behaviour which prohibits, among a long list of banned items, the wearing of any brand that is not an official Olympic sponsor.

Large armed men will be on hand to ensure that Pepsi Max T-shirts and Burger King wrappers are removed, along with their owners if necessary, from the stadiums. Multinational sponsors like McDonald's and Lloyds have been promised a "clean city", which means that they will have a monopoly on the aesthetic environment of the Olympic Park and surrounding areas. Political slogans are also banned – Che Guevara T-shirts are specifically forbidden – and anyone found carrying cardboard, paint or anything that could be used to stage even the most minor bit of placard-wagging will be refused entry. Behind the checkpoints and the missile-protected ring of steel bristling with private security, the Olympic Park will be a politics-free zone.

That, of course, is one of the biggest, most expensive political statements on the planet. The whole thing is shaping up to be about as perfect a pageant of what passes for international values in 2012 as anyone could imagine. Lots of ordinary working people have seen their homes cleared and levelled to make way for a largely publicly funded celebration of global corporate hegemony in an enormous glittering fortress behind whose walls, we are assured, a lot of good, clean fun will definitely be had, or else. Spectators will be herded through an enormous purpose-built shopping centre, encouraged to visit the world's largest McDonald's, and have their every purchase and brand endorsement monitored and policed. It's all stage-managed by a multi-million-dollar global military enforcement machine whose one redeeming feature is its shambling incompetence. Finally, of course, there are the exploited migrants doing the dirty work.

This week, it was revealed that cleaners from a variety of countries have been put up in temporary slums, paying £550 per month for the privilege of sleeping 10 to a room in flooded portable housing. If the Olympics are a festival of global prosperity in microcosm, they are an unnervingly accurate one, right down to the underpaid, precarious workers shipped in to do the rotten jobs. And that's the big secret of contemporary capitalism – much as it serves states to posture about border control and indulge in anti-immigration rhetoric, modern economies cannot function without the movement of cheap labour, usually illegally, across borders.