Michael Phelps sat alone, thoroughly exhausted. He put his head in his hands and then motioned at his neck as though he had nothing left to give.

Michael Phelps won the 17th Olympic gold medal of his career, and his 21st overall, when he produced a majestic performance in the 100m butterfly.

Rebecca Adlington claimed her second bronze medal of the London Olympics as 15-year-old Katie Ledecky produced the second fastest 800 metres freestyle in history to take gold for the United States.