As a metaphor for the London Olympics, it could hardly be more stark. The much-derided "Wenlock" Olympic mascot is now available in London Olympic stores dressed as a Metropolitan police officer. For £10.25 you, too, can own the ultimate symbol of the Games: a member of by far the biggest and most expensive security operation in recent British history packaged as tourist commodity. Eerily, his single panoptic-style eye, peering out from beneath the police helmet, is reminiscent of the all-seeing eye of God so commonly depicted at the top of Enlightenment paintings. In these, God's eye maintained a custodial and omniscient surveillance on His unruly subjects far below on terra firma.

The imminent Olympics will take place in a city still recovering from riots that the Guardian-LSE Reading the Riots project showed were partly fuelled by resentment at their lavish cost. Last week, the UK spending watchdog warned that the overall costs of the Games were set to be at least £11bn – £2 bn over even recently inflated budgets. When major infrastructure projects such as Crossrail, speeded up for the Games, are factored in, the figure may be as high as £24bn, according to Sky News. The estimated cost put forward only seven years ago when the Games were won was £2.37 bn.

With the required numbers of security staff more than doubling in the last year, estimates of the Games' immediate security costs have doubled from £282m to £553m. Even these figures are likely to end up as dramatic underestimates: the final security budget of the 2004 Athens Olympics were around £1bn.

All this in a city convulsed by massive welfare, housing benefit and legal aid cuts, spiralling unemployment and rising social protests. It is darkly ironic, indeed, that large swaths of London and the UK are being thrown into ever deeper insecurity while being asked to pay for a massive security operation, of unprecedented scale, largely to protect wealthy and powerful people and corporations.

Critics of the Olympics have not been slow to point out the dark ironies surrounding the police Wenlock figure. "Water cannon and steel cordon sold separately," mocks Dan Hancox on the influential Games Monitor website. "Baton rounds may be unsuitable for small children."

In addition to the concentration of sporting talent and global media, the London Olympics will host the biggest mobilisation of military and security forces seen in the UK since the second world war. More troops – around 13,500 – will be deployed than are currently at war in Afghanistan. The growing security force is being estimated at anything between 24,000 and 49,000 in total. Such is the secrecy that no one seems to know for sure.

During the Games an aircraft carrier will dock on the Thames. Surface-to-air missile systems will scan the skies. Unmanned drones, thankfully without lethal missiles, will loiter above the gleaming stadiums and opening and closing ceremonies. RAF Typhoon Eurofighters will fly from RAF Northolt. A thousand armed US diplomatic and FBI agents and 55 dog teams will patrol an Olympic zone partitioned off from the wider city by an 11-mile, £80m, 5,000-volt electric fence.

Beyond these security spectaculars, more stealthy changes are underway. New, punitive and potentially invasive laws such as the London Olympic Games Act 2006 are in force. These legitimise the use of force, potentially by private security companies, to proscribe Occupy-style protests. They also allow Olympic security personnel to deal forcibly with the display of any commercial material that is deemed to challenge the complete management of London as a "clean city" to be branded for the global TV audience wholly by prime corporate sponsors (including McDonald's, Visa and Dow Chemical).

London is also being wired up with a new range of scanners, biometric ID cards, number-plate and facial-recognition CCTV systems, disease tracking systems, new police control centres and checkpoints. These will intensify the sense of lockdown in a city which is already a byword across the world for remarkably intensive surveillance.

Many such systems, deliberately installed to exploit unparalleled security budgets and relatively little scrutiny or protest, have been designed to linger long after the athletes and VIPs have left. Already, the Dorset police are proudly boasting that their new number-plate recognition cameras, built for sailing events, are allowing them to catch criminals more effectively.

In Athens, the $300m "super-panopticon" CCTV and information system built for the Games following intense US pressure remained after the event, along with the disused sports facilities. In fact, the system has been used by Greek police trying in vain to control the mass uprisings responding to the crash and savage austerity measures in the country.

It is important to remember that all this is ostensibly designed to secure the spectacle of 17,000 athletes competing for 17 days. Even if London's overall security budget remains similar to that of Athens, that works out at the startling figure of £59,000 of public money to secure each competitor or £3,500 per competitor per day. In 2004, the cost in now-bankrupt Athens was £90,000 per competitor (for a smaller number of athletes than are likely to attend London). This was a major contributor, as part of the overall £10bn costs, to Greece's subsequent debt crisis.

In the context of post-austerity Britain, these figures are eye-watering. Even more remarkably, given that Olympics budgets have drawn down from many other public and lottery funds, and are no doubt adding hugely to UK national debt, the Daily Telegraph recently argued that the security operation for the Olympics were "key to aiding the recovery of UK plc".

How can we make sense of this situation? Four connected points need emphasis here. The first is that, amid a global economic crash, so-called "homeland security" industries – a loose confederation of defence, IT and biotechnology industries – are in bonanza mode. As this post 9/11 paradigm is being diffused around the world, the industry – worth $142bn in 2009 – is expected to be worth a staggering $2.7tn globally between 2010 and 2020. Growth rates are between 5% and 12% a year.

The UK, long an exemplar "surveillance society", is especially attractive to these industries, especially when hosting the Olympics. Recent security industry magazines have been full of articles excitedly extolling the Olympics as a "key driver of the industry" or as "keeping the market buoyant".

Nation states, and the EU, are struggling to ensure that their corporations get a piece of the action in markets long dominated by US and Israeli firms. Ramping up surveillance is thus now as much a part of economic policy as a response to purported threats.

The security boom is unaffected, or perhaps even fuelled, by the global crash, as wealthy and powerful elites across the world seek ever-more fortified lifestyles. Essentially, it is about defence and security corporations building huge new income streams by systematically exploiting three linked trends: the lucrative possibilities created by post 9/11 fears; widening privatisation and out-sourcing in the context of deep austerity programmes; and the desire of big city and national governments to brand themselves as secure destinations for major global events.

Booming security markets are so lucrative that accusations of corruption are often made. Siemens, a major security contractor at Athens, allegedly paid huge bribes to get the job from its internal slush fund.

Crucially, though, as Naomi Klein points out in her book The Shock Doctrine, the security boom also involves attempts to diffuse the technologies honed in counterinsurgency and colonial war in places such as Gaza, Kabul and Baghdad – drones, helicopters, data mining, biometrics, security zones, so-called "non-lethal weapons" (devices used to disperse crowds) – to the domestic "global" cities of Asia and the west.

Particular glee that Israeli-style security arrangements are now being widely implemented is evident among the CEOs of large Israeli security and defence contractors, which are doing especially well in the security boom. Leo Gleser is president of ISDS, a company that proudly proclaims that it was established by ex-Mossad agents and which was involved in £200m worth of security contracts for the Athens Games. He talks of "growing tsunamis of violence, criminal acts, and global insecurity triggered by the 9/11 events" which made the "the western world finally understand that measures had to be taken".

Olympics are especially important opportunities to cement the security boom still further. They are the ultimate global security shop windows through which states and corporations can advertise their latest high-tech wares to burgeoning global markets while making massive profits.

"The Olympics is a tremendous opportunity to showcase what the private sector can do in the security space," a Whitehall official was quoted recently as saying in a Financial Times defence supplement. "Not only do you have a UK security kitemark on the product but you've got an Olympic kitemark to boot."

The main security contractor for the London Olympics – G4S, more familiar under its old Group 4 moniker – is the world's largest security company. Beyond its £130m Olympic security contracts, it operates the world's largest private security force – 630,000 people – taking up a myriad of outsourced contracts. It secures prisons, asylum detention centres, oil and gas installations, VIPs, embassies, airports (including those in Doncaster and Baghdad) and infrastructure, and operates in 125 countries.

According to its website, G4S specialises in particular in what it terms "executive style life-support in hazardous environments". (Presumably this refers to Baghdad and not east London.) After buying up the ArmorGroup security company in 2008, it also now runs a large number of operations in Iraq. This month it was announced that G4S will also be the first private security corporation to run UK police stations with over half of Lincolnshire's police force actually moving over to the company.

The second point is that the homeland and Olympic security boom is being fuelled by the widening adoption of the idea of "asymmetric" war as the key security idea among nation states, militaries and corporations. Here, rather than war with other states, the main challenge for states is deemed to be mobilising more or less permanently against vague non-state or civilian threats that lurk within their own cities and the infrastructures that connect them.

In practice, such a shift has massive and troubling implications. As we have seen with the so-called war on terror, it works to dramatically blur longstanding legal, political and ethical lines demarcating war and war-like acts from peace and criminal acts. It also fuses policing, military operations and the intelligence services much more closely as all three seek to build bigger and bigger surveillance operations to try to predict threats, especially those within the vulnerable labyrinths of big cities.

Such an approach translates easily into a deep suspicion of cosmopolitan cities, multi-ethnic populations and the rights of migrant citizens, a process accelerated by the 7/7 atrocities in London the day after the Olympics were announced in 2005.

In May 2011 the Metropolitan Police announced that they were redeploying 290 cameras that had been installed as counter-terror systems in two predominantly Muslim areas of Birmingham to London for the Games. Recently, the Home Office warned Waltham Forest Council – home of part of the Olympic Park – that it is home to a large group of radicalised second- and third-generation Asian Britons who potentially pose a terrorist threat to the Games.

More visibly, this shift means that the familiar security architecture of airports and international borders – checkpoints, scanners, ID cars, cordons, security zones – start to materialise in the hearts of cities. What this amounts to, in practice, is an effort to roll out the well-established architecture and surveillance of the airport to parts of the wider, open city. The "rings of steel" around the City and Docklands in London were early examples of this.

The third explanation for the Olympic security boom is to be found by looking in more detail at how risks are considered in planning the events since the 9/11 attacks. Olympics security operations have grown beyond all recognition since 2000 because they have been shaped by new types of risk assessment.

The symbolic importance and prestige of the Games for cities, nations and corporations has meant that historical ideas of proportionality have basically been abandoned. Instead, as Canadian sociologists Phil Boyle and Kevin Haggerty have shown, security planning has tried to create the impossible illusion of total security by countering all threats, no matter how outlandish, unlikely or nightmarish.

Crucially, all such threats are now deemed equally valid. A model developed by the Rand corporation to help with planning for the London Games outlines in detail 27 possible threat scenarios and the means to counter them. Meeting them helps also to demonstrate the awesome power, and elite status, of the host city or state in the wider world.

This helps account for the ever-more baroque security and surveillance operations surrounding Olympic events. It also helps explain how, under enormous pressure from the US – whose security corporations benefited hugely in the process – the security budget for Sydney ($180m, or $16,000 an athlete) was multiplied eight times for Athens only four years later ($1.5bn and $142,000, respectively). The Beijing operations, in an authoritarian country, not surprisingly eclipsed both Athens and London and came in at a staggering $6.5bn.

The final point is how the security operations of Olympics have major long-term legacies for their host cities and nations. The security preoccupations of Olympics present unprecedented opportunities to push through highly elitist, authoritarian and speculative urban planning efforts that otherwise would be much more heavily contested – especially in democracies. These often work to "purify" or "cleanse" diverse and messy realities of city life and portray existing places as "waste" or "derelict" spaces to be transformed by mysterious "trickle-down effects". The scale and nature of evictions and the clearance of streets of those deemed not to befit such events can seem like systematic ethnic or social cleansing. To make way for the Beijing Games, 1.5 million were evicted; clearances of local businesses and residents in London, though more stealthy, have been marked.

Such efforts often amount in effect to expensive, privatised, elitist and gentrifying projects such as the Westfield shopping centre in Stratford (the first UK shopping centre, incidentally, to have explosives scanners at all entrances).

During the Games themselves, so-called "Olympic Divides" are especially stark. In London, a citywide system of dedicated VIP "Games lanes" are being installed. Using normally public road space, these will allow 4,000 luxury, chauffeur-driven BMWs to shuttle 40,000 Olympic officials, national bureaucrats, politicians and corporate sponsors speedily between their five-star hotels, super-yachts and cordoned-off VIP lounges within the arenas. It has recently been shown that wealthy tourists will be able to enter the VIP lanes by purchasing £20,000 package trips.

Ordinary Londoners, meanwhile – who are paying heavily for the Games through council tax hikes – will experience much worse congestion. Even their ambulances will be proscribed from the lanes if they are not running blue lights.

More broadly, a huge increase in land values tends to benefit only the wealthy property speculators and financiers that are best placed to ride the wave. Already, the Qatar royal family have bought the 1,400 homes of the Olympic village in a deal worth £557m.

Looking at these various points together shows one thing: contemporary Olympics are society on steroids. They exaggerate wider trends. Far removed from their notional or founding ideals, these events dramatically embody changes in the wider world: fast-increasing inequality, growing corporate power, the rise of the homeland security complex, and the shift toward much more authoritarian styles of governance utterly obsessed by the global gaze and prestige of media spectacles.

• Stephen Graham is professor of cities and society at Newcastle University. His latest book, Cities Under Siege, is published by Verso, priced £14.99. To order a copy for £14.99 with free UK p&p, go to theguardian.com/bookshop or call 0330 333 6846