10 August 2012 Last updated at 20:59

Olympic athletics: USA smash world record in relay win

USA's women's 4x100m relay team smash the world record to secure Olympic gold.

The winning time of 40.82 breaks the mark of 41.37, which was set in 1985 by East Germany.

Jamaica came second with Ukraine in third.

Available to UK only.

Watch a full replay of the race on BBC Sport's Interactive Video Player.