Royal Marines in inflatable boats will be stationed along the length of the Boat Race course on Sunday to ensure the event is not disrupted by another protester in the water.
Last year's race had to be halted when Trenton Oldfield swam into the path of the two crews and narrowly avoided being struck by an Oxford oar as he attempted to sabotage an event he regarded as elitist. As a result, David Searle, the Boat Race executive director, promised an improved security presence along more than eight miles of Thames River bank and warned against anyone taking to the water.
"We are taking additional measures this year and have reviewed all our actions last year in detail," Searle said. "The Boat Race course is four and a quarter miles long so we have eight and a half miles of river bank to manage and monitor.
"There will be an increased presence on and off the water, including support from the Royal Marines, but as with any security plan I cannot disclose the exact details.
"What I would say to anybody thinking of disrupting the race is that it's unbelievably dangerous. You risk injuring yourself, the crews and the other people following the race. Nobody wants that to happen. This is just a sporting event."
Oldfield was released from prison in December, having served seven weeks of a six-month sentence after being found guilty of causing a public nuisance. The Metropolitan Police contacted Oldfield by letter and on Twitter to establish whether he was planning any action this year, saying they were "keen to facilitate any peaceful protest".
In a statement, the police stressed they were not offering to organise a protest for Oldfield but to afford him the opportunity to exercise his "lawful rights without causing disruption or danger to themselves or others".
However, Oldfield told The Spectator that he would be nowhere near the Tideway on Sunday. "In spite of the Metropolitan Police's kind offer I'll probably have a ramble across the Cotswolds instead," he said.
Last year's race was eventually restarted after Oldfield was fished out of the water but his intervention was only the start of the drama. Oxford, who had been narrowly ahead when the race was stopped, suffered a broken oar in a clash soon after the restart and ended up losing by more than four lengths.
Oxford bowman Alex Woods then passed out after his crew had crossed the finish line and was taken to hospital by ambulance, where he spent the night before being discharged.
Matthew Pinsent, the former Olympic rower, is this year's umpire, having served as an assistant last year. He said: "Last year was just chaotic for the guys involved in the race – a Boat Race has seldom been stopped before – so the umpire needs the ability to deal with that decision-making and get the race started again."