Picture of the day: A swim in the park

Competitors dive into the The Serpentine lake in Hyde Park yesterday as the World Championship Series Triathlon came to London.

Britain's Alistair Brownlee (above) won the men's event, completing the 1,500m swim, 40km bike ride and 10km run in one hour 50 minutes, crowning a spectacular double-header for Team GB after 27-year-old Helen Jenkins from Wales won the women's race on Saturday. Their victories mean that both athletes have secured their place at the Olympics next year.

The weekend's events, in which 4,500 amateur athletes were also put through their paces, were a trial run of the proposed triathlon route for the 2012 Games. Hyde Park is one of seven legs in the World Championship series, with Beijing hosting next month's finale.