A wetsuit-clad protester was arrested Saturday after swimming out into the River Thames to disrupt the world famous Oxford-Cambridge Boat Race.
The two university rowing crews were forced to stop after the man, named by Sky News sources as Trenton Oldfield, a director of a group called This is Not a Gateway, paddled into their path.
Sergeant Chris Tranter of the Metropolitan Police said the rowers' oars were so close they "almost took his head off."
Oldfield was taken away by police after being pulled from the river. He is being held at a west London police station while inquiries are carried out, police said.
He wrote on his "Elitism Leads To Tyranny" blog beforehand that the swim was "A protest, an act of civil disobedience, a methodology of refusing and resistance."
He described the Boat Race as "a public event, for and by the elites with broader social relations aims."
The University of Cambridge won the 158th running of the Boat Race after it was restarted from near Hammersmith Bridge after about 30 minutes. Oxford broke an oar allowing their rivals to win back the title.
President of the Oxford University Boat Club Karl Hudspith blamed Oldfield after the defeat.
He wrote on Twitter, "To Trenton Oldfiled (sic); my team went through seven months of hell, this was the culmination of our careers and you took it from us."
The crews were neck-and-neck when the race was stopped between the two and three-mile markers of the four-and-a-quarter mile (6.84km) race.
Umpire John Garrett said it was British Olympic gold medalist rower Sir Matthew Pinsent, who was assistant umpire, who spotted the swimmer.
"He basically said, 'There's something in the water, there's something in the water'. He thought it was some debris and then we realized that it was actually a swimmer."
After the race had been completed there was more drama as a member of the Oxford crew collapsed.
Alexander Woods had to be lifted from the bow of the boat and was given emergency medical treatment.
The world-famous event is broadcast in 200 countries and attracts around 250,000 people to the banks of the Thames.