Doug Allan is Kirsty's castaway this week.
He's spent thirty-five years capturing unique footage of animals in some of the most remote and least hospitable places on earth. If you've watched fuzzy little polar bear cubs frolic in the frozen wilderness or slick killer whales eerily circling their prey, the spellbinding footage is his. David Attenborough, a long- time collaborator describes his work, simply, as "extraordinary".

A trained biologist he first made a living diving into the icy rivers of Scotland searching among the mussel-beds for pearls; a useful early lesson in patience and coping with the cold. His subsequent dedication to a working life in the wilderness has bagged him a slew of Baftas and Emmys but there's also been an emotional toll - he's coped with periods of depression and is twice divorced.

He says, "Big animals are my passion. I particularly love working with large mammals because they're intelligent and you can develop a relationship with them"

And he's at his happiest at -18 degrees centigrade!