How Eton, rootlessness and Graham Greene helped forge a giant of travel writing

What is it about Graham Greene that interests you?

I could give lots of reasons, but I wouldn't believe them myself. I could say we share the same upbringing to some degree, having grown up in middle-class Britain and having gone to the same boarding school, and that because of those years at boarding school, we never settled down into households. I could say it's because I also found my way to Saigon, Paraguay and Tahiti - places which he made famous in his writing. I could say it's because I am drawn to his interest in the complexities and riddles of faith. But I believe that the power of this affinity lies in mystery. It's because you can't explain the connection that makes it interesting.

And yet you wrote that if you had your choice of men occupying your head it wouldn't be Greene. If you could choose, who would your fantasy mentor be?

All of us have fantasy figures. As a little boy, it might have been a star in the NBA, an accomplished soccer player, James Bond, or some similar glamorous figure with which we like to associate ourselves. Greene is the master of unsettledness and patron saint of doubt; he's not the steadiest person to align oneself with.

You write about your and Greene's boarding school years at Eton and how that shaped your approach to the world. How did it shape you both as writers and travellers?

English boarding schools train you for terrible food, acute discomfort and all the horrors of being in a military campaign. To this day, most of the travel writers we know and cherish are products of that system. If you are in Afghanistan, huddling in caves and eating rocks, basically you are in boarding school again. You also have that gap year before university and the assumption is that you would spend that year going to do something interesting in remote parts of the world. I spent three months with a school friend travelling through Bolivia. We went by bus from Tijuana [Mexico] to La Paz [Bolivia] and flew up the eastern coast of South America. Then we separated and I flew to Trinidad, then Barbados and on to Miami.

What careers does the boarding school experience groom you for?