By day, 55-year-old Peter Tickler is a quiet churchgoer and computer programmer. But by night, he enters the wrong side of town — the drab side streets of Cowley and the bohemian quarter of East Oxford, populated by the homeless, mentally ill and ‘creative’ art students, where dead bodies float along the Thames.

After he finishes his day job at the Potato Council in Cowley, he returns home to conjure up the fictional world of Det Insp Susan Holden, a sleuth who battles with sexism and a mountain of personal problems as well as a mounting pile of bodies.

Peter is already working on a sequel to his first crime novel, Blood on the Cowley Road, which he wrote after taking a correspondence course with The Writers’ Bureau. The book has been so successful that it has been reprinted even before its launch date, thanks to word-of-mouth recommendations.

He said: “If there’s anything that annoys me, it’s the portrayal of the city in films like The Oxford Murders. I was determined not to set my book in tourist Oxford. Although I was at Keble College, it was a long time ago, and the book is really about town, not gown.

“I like the Cowley Road. In many ways, it’s the most interesting part of Oxford.”

There’s plenty of enjoyment for local readers, not least because the story occurs in the halcyon days when Oxford United were in a different league.

“When I started to write, they hadn’t been relegated, so I left things as they were. I have invented a few games because I needed to, for the plot, but basically, it’s all correct. I am a supporter, and I like to put in a few jokes for the fans.

“There’s a reference to Paul Wanless, for instance, who was notoriously tubby at one stage of his career.”

Without giving away too much of the plot, it is fair to say that records of match attendance play a crucial part, after the police discover that some of the suspects, apparently unconnected, were together in the Oxford Mail stand at the Kassam Stadium. While investigating which character attended which game, the police get to watch a match. Oxford score a minute after half-time and then concede a goal two minutes later. And that, in terms of goals and excitement, was pretty much that. “If that doesn’t put you off football, nothing will,” says one gloomy police officer to another.

It’s easy to picture where the characters are as they walk along the Cowley Road, or move from Wytham to Wittenham Clumps. But at one point, the police drive around the Plain roundabout, turn into Cowley Road, then immediately left into — a multi-storey car park! The book opens with the apparent suicide of Sarah Johnson, who has plunged from the car park’s top floor.

“Obviously, there are bits that you make up. It’s probably the car park in Cowley, which I have transposed to a different place. But mostly, the locations are fairly accurate. Det Insp Holden lives in the road just down from me, in Grandpont, and her mother has just moved into the retirement complex there.

“I go to St Matthew’s Church, and some of the characters come from that. I thought it would be fun to have a detective with a born-again Christian as a mother, and to have her mother praying for her.”

In fact, his transformation from computer programmer to crime novelist is not as unlikely as first appears. After his classics degree, Peter worked in publishing in London, did a further degree and produced a successful non-fiction book called The Modern Mercenary. With a young family and needing to make more money, he took a crash course in computer programming and joined the then Potato Marketing Board more than 20 years ago.

At first he found it difficult to find the time to write, but decided to take a course once his children were older. “It’s difficult when you work full-time. I tend to devote two or three evenings after work to it, but my most productive time is on holiday. We tend to go to remote places, and you need something to do when you are there.”

His wife works in mental health and Peter volunteers for Mind at a day centre in East Oxford very much like the one which features in his novel. As for the police, he said: “If you watch enough telly you know how people expect the police to behave. I have tried to make it as authentic as possible.”

Despite his attachment to East Oxford, he reveals that, in the sequel, Det Insp Holden will be venturing into the posher areas north of the city.

“I have to decide where it’s going. I like writing because it takes you into a different world.”

l Blood on the Cowley Road is published by Robert Hale at £18.99.