Whodunnit series “Midsomer Murders,” Britain’s biggest drama export, celebrates its 20th anniversary this year. How has it maintained its passionate global fan base?

On the first day of filming of the 20th season, lead actor Neil Dudgeon, who plays police detective John Barnaby, sits on the banks of the Thames River pondering the enduring appeal of Bentley Productions’ murder mystery, whose latest season has been sold by All3Media Intl. to more than 170 territories.

One aspect of the show — set in a bucolic English county comprised of picturesque villages — that sets it apart from the crime genre crowd is that it is “quirky and off-center,” he says, and laced with hefty doses of “eccentricity and humor.”

Dudgeon, who is in his seventh season after taking over from original star John Nettles, adds that the view of the English as “genteel, reserved and well-mannered” within the context of the idyllic countryside works as a counterpoint to the deceit and wrongdoing uncovered by the detectives.

“It’s like you are in the woods and you find some beautiful log and turn it over and all the woodlice, spiders and beetles come running out from underneath,” he says.
One distinctive feature of the show is the exotic nature of the murders. Dudgeon’s favorite is where a man is found dead in the woods: He has been tied to a tree, his naked body smeared with truffle oil … and eaten alive by wild boar.

Jonathan Fisher, who recently took over as the show’s exec producer, has more bizarre deaths lined up, including one where a man’s head is encased in chocolate to become a grotesque Easter Egg.

Like Dudgeon, Fisher likes the juxtaposition of the “chocolate-box view of rural English life” and its “dark, often gothic, blood-splattered” underbelly. He adds: “It’s pure escapism, and given everything that is happening in the world that is a real source of joy for our fans.”

Occasionally, there is also a “hint of the supernatural,” although come the denouement the killer’s motives must be shown to be “as emotionally truthful as possible,” Fisher says. “Everything, ultimately, has to be explained in the real world, but we can get quite spooky.”

The show is based on a series of novels by Caroline Graham, and it was former producer Betty Willingale, a consultant on the show now, who first spotted their TV adaptation potential. When the project was pitched to British broadcaster ITV, it was she who pushed for Nettles to be cast as detective Tom Barnaby, who was replaced in season 13 by his cousin. The series has found U.S. fans through PBS, Acorn TV and Netflix.

“As a central character he’s rather ‘still,’” Willingale says. “It isn’t a role that goes deep into investigative techniques or forensic analysis … but he does present this very British approach to the role. And that approach is to look largely unperturbed and just carry on.”

Another of the show’s strengths is the plethora of well-known guest actors, such as Simon Callow and Susan Hampshire. Fisher says: “We are allowed to have quite flamboyant theatrical figures and in doing so we are able to attract a stellar cast pretty much every week.”

In his notes to the writers he often eggs them on to “push the idiosyncrasies of the guests as far as possible,” he says.

Casting director Louise Cross, who has been with the show from the start, says: “We tend to have strong characters on the page, unlike a lot of modern television, so we pluck from the world of theater actors quite often in order to get a varied performance and a strong sense of character.

“Often these days TV requires a low-key naturalistic performance, but in the world of ‘Midsomer’ actors have a bit more of an opportunity to play and have fun with their roles, and I think that’s what attracts them to the show. They get to act, to give a performance.”