I’ve lived in England for thirteen years, on and off, with stints in Edinburgh, Inverness and Australia. Aside from Cumbria, which is the closest thing to home I’ve felt in my adult life, and London, which is a bubble, I often feel a stranger here. Despite moving around so often, there are big chunks of the country I’ve never seen. East Anglia is one of them. We spent this weekend exploring the area as research for my next novel, which is called Grisleymires. On Friday we drove down a smart diagonal sweep across the country from Burneside in Cumbria to Kirby Cross, almost on the Naze, and stayed the night with friends. On Saturday morning we jagged back up to Wisbech, stopping at Wicken and Ely. For the first time, I’ve been to the Fens.

Grisleymires has been in the back of my head for a while. From the beginning, I knew that it was set in a swamp – the earliest incarnation of the story was essentially Time Bandits with bog bodies. It’s evolved massively since then, but the marsh has been a constant: I want to write about mud and water. I’m now quite secure in the plot, but the location has been troubling me. Location is crucial to the way I write, and I didn’t feel confident in my knowledge of any British bogs. I picked the Fens on instinct, and decided to find out more from there.

The first person I spoke to about Fenland felt so negatively about it that he could only laugh hysterically. He’s one of the most articulate people I’ve ever met, and he simply couldn’t formulate words to describe how powerfully it repelled him. That was exactly the sort of start I was hoping for. Since then, people have told me that the Fens are creepy, strange, powerful and weird. Everyone talks about ‘big skies’. Now that I’ve driven through them, I can understand why. It’s the flattest landscape I’ve ever seen. The horizon is broader, the perspective unnerving, the sky an impossible bowl. There are miles at a time without undulation – miles without trees. Ditches run in straight lines to vanishing points. In places, roads run lower than canals, with dykes and bridges guiding the contours. It’s especially strange near the coast, where the horizon is curtailed by the shore.

We stopped at Wicken Fen, where I stood in the blustering wind and stared into the winter sun. Tall grass became an ocean and hissed at me in waves. I never expected so much noise from emptiness. The sun turned orange, and the dusk turned blue, and pylons hung like giants against the scraps of cirrus. At one point, we drove along beneath a dyke for a mile or more. The road turned sharply up the bank and at the top, blinded by sunset, the world opened up like Noah’s flood – the entire horizon drowned in water, withered trees and battered shrubs emerging in silhouette against the sun. That was the road to Wisbech, submerged in wetlands.

We drove the alternative route to Wisbech on undulating single track roads lined with Nissen huts and broken hedgerows, tumbledown houses and gigantic piles of sugar beet, surrounded all the while by thousands upon thousands of acres of thick, turned loam.

Wisbech was a strange town. The B&B was huge and empty. When we went to look for food, we found ourselves in what seemed to be a red light district. Drunken Polish men yelled at each other across the street, while girls on corners danced to techno on CD stereos. On Friday night, above the Naze, the stars were clearer than I’d seen in years; on Saturday, the sky was full of murk. On Sunday morning, we drove on Droves – lumpy roads, arrow straight for five miles or more, then zigzagging madly to meet the next. They separate broad strips of industrial agriculture, riven with canals, ditches and soakaways. All the trees wear killing coats of ivy. For the most part, we drove in silence, occasionally pointing things out to each other. The landscape was relentless without becoming monotonous.

The Fens is witchcraft and weak bridges; rotten thatch and revolution; gallows and windmills. At one point, we passed a narrowboat moored beneath a sickly weeping willow. It looked like it was about to break in half and sink. It was small, and covered with lichen, but I could still make out the name: it was called Icarus.

I don’t know if the Fens are creepy, but they are profoundly strange. We felt edgy all the time. We’re used to the cradle of the mountains, a constant presence in our peripheral vision. It’s incredibly strange to be without that subconscious company. Mon pointed out that the sheer amount of space makes you feel exposed – vulnerable. We didn’t find it creepy, so much as missing. It’s an absence, a nothing, a void. It felt like a sort of purgatory; fields unfolding endlessly, stretching on forever.

I went on this trip hoping for a sort of Green Venice, but that’s not what the Fens are about. They aren’t what I expected, or what I wanted, but maybe this trip has been exactly what I need, and here’s why:

I invented Bancree for The Visitors. It’s an amalgam of Islay, Jura, Gigha, Kintyre and the Black Isle, plus a host of other Scottish spots; and I’m already planning a novel set in a fictional city, based around my short story Vanishings. The point is this: I thought nothing of creating an island, and I can’t wait to write a city. I don’t know why it’s taken me this long to consider inventing a Fenland of my own. Writing a new region into an existing geography feels more daunting than something as self-contained as an island, but that would give me the perfect environment for Grisleymires.

I’ve only started considering this today, but it’s already gathering weight. It would let me combine the heat and life of Green Venice with the sodden bogs of Islay and the upland Cumbrian basin mires with the Fens and Norfolk Broads. I could do as I pleased with accents and geography and culture, and that’s a real magnet for me. I’d be sad to leave or even dilute the Fenland folklore, though – I’ve grown attached to Tiddy Mun and Old Shuck.

As a research trip, it’s thrown up more questions than it’s answered. But that, in itself, is part of the journey.