Nothing beats an odd couple when it comes to detective films. Think Mel Gibson and Danny Glover as the mismatched partners in the hit Lethal Weapon franchise, or Eddie Murphy as Axel Foley, the freewheeling Detroit cop shaking things up in Beverly Hills. And it’s just as entertaining in fiction.

There’s Lizbeth Salander and Mikael Blomkvist in Stieg Larsson’s Girl with the Dragon Tattoo series; Sherlock Holmes and Dr Watson, naturally; and archeologist Ruth Galloway and DCI Harry Nelson in Elly Griffiths’ Norfolk-set procedurals to name just a few. But Simon Mason might just have pipped them all with the most brilliant (and possibly dysfunctional) pairing of partners yet – DIs Ryan Wilkins and Ray Wilkins, whose fifth book, The Dangerous Stranger, has just been published

The surname-sharing pair are memorably described as Thames Valley Police’s ‘pantomime horse’ – one (Ray) Oxford-educated, the other (Ryan) from an Oxford trailer park – and while the books might be set in the City of Dreaming Spires, Inspector Morse they ain’t! But with fans including the likes of Stephen Fry, Val McDermid and Mick Herron – who describes Wilkins and Wilkins as “crime fiction’s most entertaining double act in decades” – plus a growing buzz among readers, Mason, 64, is onto a winner.

In part, it’s about playing with stereotypes but the result is one of crime fiction’s most refreshing new series in years.

“Ryan is what we might call a chav,” explains Mason, a former publisher of literary fiction and writer of young adult books. “You see him in the street, baggy tracky bottoms, shell suit jacket, plaid baseball cap, big bling and can of energy drink on the go and you might assume he’s a member of the criminal classes.

“You think he’s probably got a big dog on a chain, three or four kids by three or four different women and has never done a day’s work in his life. So I flipped that completely. He did grow up in a trailer park and he has got a massive chip on his shoulder but he’s also got lots of native intelligence and he sees things other people don’t. In fact, he’s a doting dad to a three-year-old son, Ryan Jnr. If you grew up in a trailer park with injustice all around you and a violent, alcoholic father, that might well inspire you to join the police.”

When the ADHD, rave-loving, Red Bull guzzling detective “swaggered” into Mason’s imagination almost fully formed – “I don’t know where from, that’s the honest truth, but something in me must be rebellious because I keep writing these characters – the author knew he needed a straight man with whom Ryan could be “really mismatched”.

Enter Ray Wilkins: double-first from Oxford, Boxing Blue, privately educated and happily(ish) married. And in contrast to Ryan, Ray does everything by the book making for some highly entertaining friction.

Mason, who introduced the pair in 2022’s A Killing in November continues: “At an event, someone asked me why Ray is black and I just said without thinking, ‘Because Ryan’s white’, it was as simple as that. Ryan’s White, not good looking, not educated, no manners, terrible dresser, and Ray’s the opposite – suave, sophisticated, handsome and knows how to behave in elevated company.

“So when you throw them together, you get fireworks. What that comes from is an interest first and foremost in character. In all the stories, I’m trying to come up with something that is exciting, but which also creates a drama of character.

“But beyond the characters themselves, Oxford is a place of richness and poverty, privilege and influence, advantage and disenfranchisement – it’s the city of those contrasts. That dramatic disparity is one of the very obvious stories of our time. So they give me an in to discuss things like wealth or privilege inequality.”

The Dangerous Stranger couldn’t be more timely, with Wilkins and Wilkins investigating a murder during a riot at an asylum seekers’ hotel. Initially, it seems an open and shut case of far-right violence. But appearances can be deceptive and when they discover their victim wasn’t a resident of the hotel – let alone an asylum seeker – things start to get really weird.

While it’s Ryan whose career has been, frankly, on a knife edge in the past few books, this time Ray is struggling. His marriage is suffering under the workload, he’s second-guessing himself, the Superintendent is on his back, and it sometimes seems it’s him, not Ryan, who is likely to lose his self-control. All you can do is sit back and enjoy the ride.

The books seem tailor-made for the small screen but, as Mason admits, television is a slow-moving world. That said, crime dramas depend on fresh characters and there is something genuinely different about Wilkins and Wilkins.

Not content with one acclaimed series, Mason, a father of two grown-up children who lives in Oxford, has another strand to his fiction; his ‘finder’ books featuring Talib, an Iraqi-born former police detective who specialises in tracking down missing people. Written as a “palette cleanser”, they have all the originality, style and concise, character-driven class of George Simenon’s Maigret novels plus some similarly great titles – the latest being The Woman Who Laughed.

“When I decided I wanted to write something different from crime novels, I thought a missing persons investigation might be good, so I went online and Googled and you get absolutely dozens of real-life stories,” he explains.

“Losing someone is a visceral, emotional experience. If your daughter goes missing, or your best friend or your husband, and they’re never seen again you can only imagine the impact.”

His investigator, he confirms, was part-based on Simenon’s Inspector Maigret.

“Maigret’s constantly going to meet people to ask questions and they give him information like, ‘Yes, I heard a noise on the stairs’. A lot seems very extraneous until it’s time to bring it all together. My narrator is like that, he’s very empathetic, he’s a listener.”

Talib is an Iraqi Jew who grew up in Baghdad before his parents sent him to live with an uncle in Paris to finish his schooling, and then to university in England.

“It’s cultural appropriation on a massive scale,” Mason chuckles. “But he’s a very cosmopolitan, literate person. He’s always been quite withdrawn but he married and his wife and son were killed in a road accident so he’s got this loss in his life. Those people are never coming back but he was always good at finding others.”

Do yourself a favour and find Simon Mason’s books asap.

• The Dangerous Stranger (Quercus, £16.99) is out now in hardback, ebook and audiobook