A protester who disrupted this year's Boat Race by swimming into the path of the crews was found guilty today of causing a public nuisance.
In front of millions of television viewers, Trenton Oldfield, 36, halted the annual race between Oxford and Cambridge universities on April 7.
He told a jury at London's Isleworth Crown Court that the race was a symbol of elitism in government.
Judge Anne Molyneux said all options were open to the court, including jail, when he is sentenced on October 19.
"Mr Oldfield has accepted that he disrupted the boat race," she said.
The court heard that Oldfield, an Australian who moved to the UK in 2001, decided to make the protest after learning of Government plans to "sell off" the NHS and "snoop" on electronic communications, and after hearing encouragement given to "dob in" people planning protests during the Olympics.
Oldfield, of Myrdle Street, east London, worked and volunteered for a decade in jobs and projects aimed at increasing better prospects for people in impoverished areas.
He stopped the annual contest for around half an hour, the first time in the history of the 158-year event that it had been disrupted by a bather.
Prosecutor Louis Mably told jurors the race between Oxford and Cambridge was spoiled for hundreds of thousands of spectators watching from the banks of the river or live on BBC TV, not to mention the two university rowing teams.
The judge said it was Oldfield's first offence and that five people had told the court he was a man of good character.
She said the 36-year-old had moved from his native Australia in 2011 and held a number of jobs in social projects. However, she said: "The court will be considering if a custodial sentence is necessary."
Oldfield hugged his partner as he was released on bail until sentencing.
During the trial Oldfield told the jury the race was a symbol of elitism in Government and that London "has the highest inequality in the western world".
He said: "(The boat race is) a symbol of a lot of issues in Britain around class, 70% of Government pushing through very significant cuts are Oxford or Cambridge graduates.
"It was a symbolic gesture to these kind of issues."
He had told the court that he decided to make the protest after learning of Government plans to "sell off" the NHS, "snoop" on electronic communications and hearing encouragement given to "dob in" people planning protests during the Olympics.
Oldfield said with coalition public spending cuts implemented, London was "kind of worse than in Dickens' time".
He said some spectators has thought his actions had improved the race. "Lots of people thought it made it the most exciting Boat Race ever," he said.
Oldfield said he had no regrets about his actions and rejected the idea he could have been hurt by the boats.
He insisted, repeatedly stating that "having grown up in Australia", he was well used to avoiding surfboards, boats, rocks and coral while swimming.
Four-time Olympic gold medal rower Sir Matthew Pinsent told the trial Oldfield could have been killed.
Sir Matthew, who was assistant umpire during April's race, made a written statement to police just hours after Oldfield was plucked from the path of the speeding Cambridge and Oxford boats.
In a statement read out to the court, he said: "The risk for the swimmer was great, he could have been killed if he had been struck by an oar or the rigging which is metal. The incident caused me alarm as one of my primary roles is the safety of the competitors and public at large."
After the case, investigating officer Detective Sergeant Matthew Hearing said: "Mr Oldfield's one-man protest was designed to disrupt an event enjoyed by thousands of people and he succeeded in holding up the race for around 30 minutes, causing serious disruption to all involved.
"I hope his conviction and the fact he now has a criminal record proves a deterrent to others intent on committing similar acts in the future and spoiling public events that should be about celebration and enjoyment."
Oldfield, accompanied by his wife Deepa Naik, made a brief statement to reporters outside the court.
"As inequality increases across Britain and much of the world, so does the criminalisation of protest," he said.
"My solidarity is with everyone working towards more equitable societies everywhere."
Oldfield then ran back into the court after he was bombarded with questions by reporters.