A protester who disrupted this year's Oxford v Cambridge Boat Race by swimming into the path of the crews has been jailed for six months.
Trenton Oldfield, of London, who was also ordered to pay £750 costs, was watched by millions of television viewers as he halted the annual race on the Thames between Oxford and Cambridge universities on April 7.
He was found guilty at London's Isleworth Crown Court last month of causing a public nuisance and returned to the same court on Friday to be sentenced.
Oldfield, supported in court by a throng of well-wishers, smirked as Judge Anne Molyneux passed sentence.
But he looked surprised as the jail term was handed down.
The judge said Oldfield had acted dangerously, disproportionately, had not shown what he was actually protesting against, and displayed prejudice in sabotaging the event which Oldfield regarded as elitist.