Ledecky collects treble with 800m win

Katie Ledecky of the United States has destroyed the field in the 800m freestyle on Friday and broke the world record to complete a rare Olympic swimming treble.

Ledecky led from the start to clock eight minutes, 4.79 seconds, beating her previous mark of 8:06.68 set in Austin, Texas in January.

Britain's Jazz Carlin won her second silver medal in 8:16.17, and Boglarka Kapas of Hungary took the bronze.

Ledecky, defending Olympic champion at the distance, added to her golds earlier in the week in the 200m and 400m freestyle and the 4x200m freestyle relay, plus a silver in the 4x100m relay.

The only previous woman to win the 200m, 400m and 800m freestyle at the same Games was American Debbie Meyer in 1968.