Doug Allan is Kirsty's castaway this week.

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!