Katie Ledecky successfully defended her 800m freestyle title by taking almost four seconds off her own world record in the final at the World Swimming Championships in Russia this evening.

The American won the race in a time of 8:07.39, beating her previous best of 8:11.00, to give the 18-year-old her fourth individual gold of the meeting.

New Zealand's Lauren Flynn finished over 10 seconds after Ledecky to pick up the silver, while Jazz Carlin of Great Britain secured the final spot on the podium, stopping the clock just 0.26 seconds ahead of Australia's Jessica Ashwood.

Carlin's bronze is her first individual medal at a World Championships, and Britain's ninth at this meeting.