HARDtalk

Today's sailors use satellite navigation and write daily web-log posts about their journeys, but when Sir Robin Knox-Johnston completed the first solo round-the-world voyage in 1969, he went eight months without radio contact. Last year, at the age of 68, Sir Robin decided to sail around the world again, but admits his first epic voyage will always mean more to him. Stephen Sackur asks him if we're running out of journeys of exploration and endurance.