LONDON, UK — When Trenton Oldfield, a 35-year-old Australian activist, jumped into the icy waters of London’s Thames river last week, the ripples traveled further than he expected.

Oldfield’s unscheduled swim, which disrupted a major university rowing race, was intended to be a statement against elitist colleges. Instead it has been widely greeted as a harbinger of the protests likely to blight the Olympic Games that the UK capital will host this summer.

It also highlights battle lines being drawn ahead of the games: Bitter clashes between officialdom and opponents that observers say will see 2012 remembered not as a glorious showcase for London but as a final, desultory kick in the ribs to a dying Olympic spirit.

London’s Olympic organizers and the UK government are spending millions of dollars on security, deploying more than 23,500 personnel to safeguard against terrorism and keep out anyone seeking a platform to air grievances.

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As previous hosts have done, the UK has enacted laws ahead of the games giving police enhanced powers to apprehend protesters and prevent demonstrations from being staged anywhere near sporting venues.

But Oldfield, who says he is willing to go to prison for his actions, appears to have unwittingly exposed a chink in this armor — one that officials admit could be easily exploited.

“It just takes, and is likely to be, one idiot,” Colin Moynihan, chairman of the British Olympic Association, told the BBC after the boat race incident. “You can never get it perfect unless you remove all the crowds and nobody is going to dream of doing that."

The problem facing Olympic organizers is that, while they are unlikely to call themselves idiots, the ranks of people who would potentially wish to visit chaos upon vulnerable sporting events — or at least attempt to steal the media spotlight — are legion.

Already, multiple anti-Olympic groups are flexing their muscles.

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Earlier this week, police and bailiffs evicted several dozen people from a camp on the building site of an Olympic basketball practice center. The camp was the vanguard of what is expected to be a series of Olympic-linked sit-ins organized by the anti-capitalist Occupy group.

This week also saw the unveiling of a manifesto for a summer of protest by UK Uncut, a direct action group (loosely affiliated with Occupy) that demands that public-sector cuts be abandoned in favor of higher taxes on big business.

The group, which has been involved in high-profile acts of civil disobedience, said it had “no plans to directly disrupt” the Olympics, but will set up nationwide roadblocks to coincide with both the games and celebrations in June marking 60 years of Queen Elizabeth’s reign.

Other protesters have focused on the big name sponsors who provide essential financial backing to the sporting spectacle, but also expose its organizers to embarrassing questions over their commitments to ethics and sustainability.

Chief among these is Dow Chemical, which has been invited to sheath the Olympic stadium in an $11-million decorative wrap, much to the fury of victims of the 1984 gas leak disaster in Bhopal, India, who insist the US firm must pay compensation and fund site decontamination. The leak left thousands dead and countless more people injured.

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Both Dow — which has been linked to Bhopal since 2000 when it acquired Union Carbide, a former parent of the pesticide manufacturer blamed for killing thousands — and the games’ organizers insist the chemical giant is not responsible, and that its Olympic involvement is beyond reproach.

But campaigners in the UK and India say otherwise. Last year, disaster survivors torched an effigy of a British Olympic official on the streets of Bhopal. And in London last month, a 28,000-signature petition against Dow’s involvement was delivered to 2012 organizers.

There have been threats of further direct action against Dow and other corporate sponsors. BP was targeted this week by a cyber stunt that used a fake London 2012 website to announce the petrochemical company had been dropped as a “sustainability partner.”

More is expected to follow as various groups form allegiances under an umbrella organization known as the Counter Olympics Network, which is due to meet this weekend to coordinate strategies.

Olympic protests are nothing new. Mexico City’s 1968 Games took place against a backdrop of student demonstrations in which several protesters were shot dead. Aboriginal campaigners targeted Sydney’s Games in 2000. Athens in 2004 was also not without incident.

There was little dissent when communist Beijing hosted in 2008, despite the provision of a state-monitored protest pen. Instead, pro-Tibet activists vented their anger outside of China, disrupting Olympic torch relays in cities such as Paris, San Francisco and (ominously) London.

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But the extent of protest leveled at London is symptomatic, according to academics, of a broader problem. They argue that by transforming the Olympics into a sanitized and profit-driven behemoth in thrall to sponsors, organizers have betrayed the amateur principles of the modern games.

“They’re very much a corporate affair now, and that of course has meant the death, in practice, of the historic Olympic idea,” said Stephen Wagg, a professor and co-editor of “The Palgrave Olympic Handbook,” a newly-published sociological study that is highly critical of the games.

Wagg said Olympic spirit has been in decline since the private sector was first tapped to pay for the Los Angeles Olympic Games in 1984. He says corporate partnerships have led to a decline in civil liberties as hosts willingly enact prohibitions to safeguard the interests of sponsors.

“The Olympics media audience is near to saturation point,” he said. “It’s massive and that’s a great attraction to Olympic partners, but they want a guarantee that this will not be disrupted in any way, that nobody brings a sour taste to the Olympic media event.”

He added: “In the world that I grew up in, the Olympics was an unambiguously good thing. ... What’s different today, politically, is that an increasing number of observers do not regard the Olympics as a straightforwardly good thing any more.”