Police have charged a man with a public order offence after "possibly the most dramatic Boat Race in history" was temporarily halted by a swimmer who appeared to deliberately cross the path of rowers.
An Oxford crew member was also taken to hospital after collapsing in his boat and a team mate's oar snapped during a day of high drama on The Thames.
Trenton Oldfield, 35, narrowly avoided the blade of an Oxford oar as he swam into the path of the vessels between the two and three-mile marker while the university crews were neck and neck yesterday afternoon.
The 158th race was stopped for almost half an hour while the wetsuit-clad swimmer was pulled from the river and taken away on a police launch before being arrested.
Oldfield, of Myrdle Street, east London, was held in custody at Chiswick police station before being released on bail last night.
He will appear at Feltham Magistrates' Court on Monday April 23 charged with a Section Five offence under the Public Order Act, Scotland Yard said.
Cambridge powered on to victory following the restart of the historic competition, but not without further drama: a clash of oars led to Oxford crew member Hanno Wienhausen breaking his blade, allowing the Light Blues to pull clear.
Celebrations were then muted as Oxford bowman Alexander Woods was taken to hospital after collapsing in his boat after passing the finish line.
The 27-year-old Pembroke College student was later said to be in a stable condition.
Oldfield studied contemporary urbanism at the London School of Economics and has a website called Elitism Leads to Tyranny, which discusses civil disobedience tactics.
Karl Hudspith, president of the Oxford University Boat Club, blamed the swimmer for ruining his crew's big day.
He wrote on Twitter: "My team went through seven months of hell, this was the culmination of our careers and you took it from us."
He said Mr Woods was conscious and "will hopefully be ok", offering thanks for the messages of support the rower had received.
He added: "I'm proud of everyone in the team and how they rowed. They were a credit to themselves and their university."
The contest ended with no presentation ceremony and the Boat Race Company described it as "possibly the most dramatic in Boat Race history".
A statement on the Boat Race Company Limited (BRCL) website added: "At this time, BRCL's concern is for Alex's well-being. Alex's family are with him and he is receiving the best possible medical care."
Sean Bowden, the Oxford University Boat Club coach, said the rower's collapse was the product of "the most extraordinary and unfortunate chain of events that have conspired against us to take away a win which I think we looked like we were about to take in the race proper".
Dr Woods must have felt desperate, he suggested.
"Obviously our biggest concern is Alex's welfare and it was good to see that he was conscious and taken off to hospital with good care," he said.
"We rowed ourselves into a very good position and the crew looked in good shape. And we were ready to go and again at the restart we put ourselves in a very good position.
"The clash was obviously just one of those extremely unfortunate things. And the outcome of the crash was a broken blade.
"And I guess you can only imagine the desperation that Alex must have been in with only six crew mates left and that's probably how he ended up pushing himself beyond his limits."
Umpire John Garrett said it was former rower and assistant umpire Sir Matthew Pinsent who spotted the swimmer in the water.
"I'm grateful to Matthew for having spotted the swimmer," he said. "He basically said, 'There's something in the water, there's something in the water'. He thought it was some debris and then we realised that it was actually a swimmer.
"We weren't sure what was going to happen, whether he was going to get out of the way in time and then it was quite clear he was just waiting for the boats to come across him so I had to stop the race and restart."
Mr Garrett also said the rules stated that crews had to "abide by their accidents".
He said: "If something happens in a latter stage of the race and there's a breakage, they have to abide by their accident, unless one of the crews is actually off-station and has caused that accident."
He dismissed an appeal from Oxford cox Zoe de Toledo for the race to be re-run.
Yesterday was the first time in the Boat Race's history that the event was disrupted by a swimmer, organisers said.
But it was not the first time it had been temporarily halted. In 2001 the race was stopped by the umpire just over a minute after the start, following repeated warnings to both crews to move apart and then a clash of blades for which Oxford was blamed.
The race was subsequently restarted and Cambridge rowed to victory.