We need to save the Arctic not because of the polar bears, and not because it is the most beautiful place in the world, but because our very survival depends upon it.

The blues is also existential and offers a sense of mature reflection that enabled it to be the leitmotif of modern life.

Of all the creatures in the world that really frighten me - the hyena in Africa, the great white shark - leopard seals are near the top of the list. They're killers. If my team spots one, they'll pull me out of the water.

If you want to swim across the English Channel from England to France - you have to leave your doubt on the beach in England.

The days of exploration of Shackleton and Scott are long gone. Everything has been climbed, crossed, done. Now what we're exploring are the full boundaries of human endeavour. It's not physical - it's all in the head.

Going against the tide has never been difficult for me. It wasn't even a conscious decision but the natural consequence of following my own instinct.

Ultimately I wanted to be a pioneer swimmer, a distant descendant of Scott, Amundsen and Hillary, except that I would be an explorer of the water.