A protester who disrupted this year's Boat Race by swimming into the path of the crews has been jailed for six months.

Trenton Oldfield, from Whitechapel in east 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 7 April.

He was found guilty at Isleworth crown court in London 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 wellwishers, looked surprised as the jail term was imposed by Judge Anne Molyneux.

The judge said Oldfield had acted dangerously and disproportionately, had not shown what he was protesting against, and had displayed prejudice in sabotaging the event, which Oldfield regarded as elitist.