HONG KONG, Nov 25 —After 20 hours and 56 minutes of non-stop swimming, Simon Holliday hauls himself up the steps of Disneyland pier, knees almost buckling, to claim a world first.

The British marathon swimmer has just survived rough seas, testing tides and cramp to become the first person to circumnavigate Hong Kong’s largest island of Lantau, a distance of over 65 kilometres.