The American swimming star Michael Phelps has claimed his fourth gold medal of the London Olympics, in the men's 4x100 metres medley relay.
Phelps's final medal tally in London is four gold and two silver, lifting his overall Olympics tally to a record-breaking 22.
The United States team finished the relay in 3:29.35 seconds, ahead of silver medallists Japan and bronze medallists Australia.
Phelps's other medals in London have come in the 100 metres butterfly, the 200 metres individual medley and the men's 4x200 metre freestyle relay.
