A swimmer "protesting about elitism" brought "chaos" to the 158th University Boat Race when he jumped into the River Thames, a court has heard.
Trenton Oldfield stopped the contest for about half an hour on 7 April.
Prosecutor Louis Mably said the race between Oxford and Cambridge was spoiled for hundreds of thousands of people.
Mr Oldfield, 36, of Myrdle Street, east London, denies the charge of causing a public nuisance.
'Feeling of disappointment'
Opening the case, Mr Mably told jurors at Isleworth Crown Court, west London, the annual event was spoiled not only for the rowing crews but the spectators watching at home on BBC TV and along the course.
He said despite it continuing, "so far as the Boat Race was concerned, Mr Oldfield had obviously caused chaos".
Mr Mably added: "The feeling of disappointment was obvious - because not only had everything been delayed but the crews and the public had been denied a natural conclusion to the race that they had come to the river to see."
He said after being rescued from the river Mr Oldfield was detained by police who asked him why he had jumped in the water.
Mr Mably said: "He replied that he was protesting about elitism.
"Exactly what he meant by that - who knows?"