In Philip Reeve's latest novel, the British empire stretches to Saturn and beyond

Larklight, your latest novel, is a lovable Victorian-era space adventure. That’s a lot sunnier than your “Hungry Cities” series, which takes place in a grim post-apocalyptic world, where cities roam around devouring one another.

I was aiming the “Hungry Cities” series at children 12 and upwards, which was the age I was when I was reading grown-up science fiction. But I do find that a lot of much younger children are reading it, and I worried slightly that it’s too bleak and violent for them. So I thought it would be nice to do something that I wouldn’t be worried about if it gets into the hands of seven-year-olds.

Mortal Engines, your first book, got rave reviews, and A Darkling Plain, the fourth and final volume of “The Hungry Cities Chronicles,” recently won a literary prize in England. For years, you made your living as an illustrator. Are you surprised by your newfound success as a writer?

Yes, completely. Through my whole life, writing has been my hobby. I thought Mortal Engines was a good enough idea to be published, but I didn’t expect it to take off the way it has. I was fully expecting to publish just one book and go back to being a full-time illustrator.

Did you originally write Mortal Engines as a children’s book?

I assumed that Mortal Engines would be too dark and bleak to be a children’s book. But in fact, I really didn’t have to change it very much to make it into one. In the original version, the central characters, Tom and Hester, were in their early twenties. I changed it so they were in their middle teens, and the story got a lot shorter and tighter. Those were all improvements.

You once told an interviewer that film companies tend to muck up movie versions of novels. Would you like to retract that now that Warner Brothers has purchased the rights to Larklight for a reported seven figures?

The option for Mortal Engines has gone now as well. One hopes that it will turn into a wonderful film. But I’m a bit worried, because I think they’ll want to make Hester pretty, for example. I think a filmmaker will be under huge pressure not to have a hideously ugly heroine and an unhappy ending in a family movie. But Larklight is already a happy family adventure story. So I’m not worried about it.

Your novels have a seductive visual quality that reminds me of director Terry Gilliam’s films. Have you seen any of them?

Terry Gilliam has been a big influence on me, especially Time Bandits and Brazil. Brazil is probably the genesis of Mortal Engines. The film’s sort of retro-future world, full of strange machinery, had a huge influence on me when I first saw it in 1985.

When you’re working on a story, how do you think—in words or images?

For a long time, I was quite a keen amateur filmmaker, and I made very elaborate movies. I still think that way when I’m thinking of a story. I see it as a film that I run in my head, and I just keep running alternative versions of it until I come up with a cut I like.

Even though you live in rural England, you often write about huge machines and sprawling cities.

I’m a city boy myself. I grew up in Brighton, which is a big coastal town close to London. I escaped to Dartmoor in search of peace and quiet and open spaces. But I can’t claim to be a country person at all.

Thanks for being such a good sport about the photo shoot.

I don’t mind being a cultural stereotype for a good cause.