If you imagine the classic British police detective, what would that person be like?

It might possibly be a man, possibly middle aged, possibly a heavy drinker, with a problematic career and a hostile relationship with his (male) superior.

In my first book – Corn Dolls – I wanted to create a policeman who was almost a photo negative of those qualities. Ok, he was a man – but he was quite young, a real high flyer, had never touched alcohol, had an intensely close relationship with his (female) boss in the Cambridge police.

What secrets would such a person hold? And what kind of conspiracy would bring them to the surface? The catalyst proved to be a small Fenland village with a well-concealed history of violence – a concealed history similar, in some ways, to the detective’s own past. I called him Tom Fletcher because it was a completely neutral name, giving no clues.

Steel Witches is the second book in this series – and, as some people have pointed out – although it’s set in Cambridge, it feels like a world away from Corn Dolls. Tom Fletcher is a private investigator now – not in the US sense, with a badge, a gun and a legal standing. He’s a PI in the British sense – the kind of marginal security man that nobody wants anything to do with. He has some of the context of the classic PI – the office, the filing cabinet, the lack of business. And the raincoat, of course (though I changed that to a parka for the Cambridge winter). And it was interesting, scene by scene, to see the viewpoint of someone who used to be a cop and now has no entitlement at all over the people he’s trying to influence. I drew some inspiration here from Walter Moseley – the way his Easy Rawlins character uses whatever leverage he can find in a situation.

So what is Fletcher up to now? Well, he’s still with Cathleen, the girl he met in a foster home at the age of sixteen and could never forget. He still lives in the centre of Cambridge, and he’s still friends with Stan, the morose Polish caterer. But now he’s talking to his father again – a man he hasn’t spoken to for 18 years. That’s because his dad phones him one morning and tells him to go to an abandoned quarry outside Cambridge, where Fletcher finds the body of an executive from a US weapons corporation. In the man’s hand is a lock of blonde hair – the hair, it turns out, of a missing physics undergraduate. For some reason, the missing girl has a photo of Fletcher himself pinned to her bedroom wall – and has been taking an interest in the American air force from world war two. That’s when Fletcher begins to realise that this is a very personal conspiracy: that someone very close to him is in danger because of events that happened on a wartime American airbase in remote Norfolk. The task of uncovering those events - and deciding if they constitute the last great secret of the war, or something else - becomes the biggest thing in Fletcher’s life.

I’m a great believer in the power of maps: that looking at maps is a huge source of ideas for both setting and plot. When I was planning this book, I spent a lot of time studying a large-scale map of Eastern England. It was amazing how often a certain shape appeared: an elongated A-shape, always facing east-west. Some of them were marked ‘Airbase (disused),’ some were unmarked, some were no more than a pattern of lines half covered by new development. These were the old airbases, of course, and as I set off to visit them, the idea for the book took shape. I had in mind an isolated house on a flat plain. I imagined two young women living there, cut off from the outside world, living on stories until the Americans arrived one day with their beautiful Mustang fighter planes, pictures of glamorous girls painted on the fuselages. What kind of passion or conflict would this arouse?

I looked at the large-scale map of Norfolk, trying to find such a house. I noticed one in the Walsingham area: still isolated today, near the site of an old airfield. It had an interesting circular formation next to it, labelled simply ‘Pit.’ As soon as I saw it, I knew it was my house: a ramshackle farm labourer’s home with nothing near it except the old runways. I parked and walked along the road to the site of the ‘Pit’ feature. It was a huge hole in the ground, surrounded by reeds, filled with oily water. I thought: Perfect. That’s going in the book.

As I write this, I’m coming to the end of the next book in the Fletcher series (the working title is ‘Cut Out’). It takes Fletcher another three years into the future, to a point where he’s achieved what he always wanted: a family of his own, and a place to call his own, on a smallholding in the Cambridgeshire countryside. Cathleen’s there, of course, and by this stage they have two young children. Life seems perfect. Except that, just down the road, there’s an army barracks with a regiment getting ready to ship out to Afghanistan. And they’re taking a close interest in Fletcher and his family.

The character who began as a photo negative of the classic detective continues to evolve. In August, when the dust from the Steel Witches launch has settled, I’ll start on book four in the series. I’m thinking of animal disease – like bird flu, but ten times worse. And a government minister who’s gone missing. And Tom Fletcher – with all his obsessive loyalties - as one of the few trustworthy people in a very dodgy world.

STEEL WITCHES
is published by Headline
June 2008 pbk £6.99

Read Adam Colclough’s opinion of CORN DOLLS