"A massive turquoise glacier feeds into Magdalenefjord, with chunks of ice as big as buildings breaking off and landing in the water to float away as icebergs. As I swam past them, with my head in the water, I heard a tantalising sound: a snap-crackle-pop, just like Rice Krispies in milk. It was the sound of tiny air bubbles being released from the ice – air that had been trapped there as much as 3,000 years ago. To swim through this sound, I thought, is to swim in history."

“I don’t know of any sport where the goalposts can shift the way they do with endurance swimming.”

“If you have a passion, follow it. It's the best barometer of what you will be good at. And choose a career that you enjoy – the extra money of a job you detest isn’t worth it.”

“I always tell young swimmers: 'Practice things until you can't get them wrong. Not until you get them right.' There's a big difference.”

“No matter how tough my day has been, when I dive into the sea, the world seems perfect.”

“The trick is to make fear your friend. Fear forces you to prepare more rigorously and see potential problems more quickly.”

“I have been haunted by that swim through the whale graveyard and haven’t been able to get the image of the bones out of my head. Man hunted whales almost to the point of extinction, not seeming to care that we would lose one of the wonders of the sea world forever. It is the coldness of the water in Antarctica that preserves the bones and makes it look like they were left there yesterday but I like to think they are there as a reminder of man’s potential for folly.”