“I like detective stories,” G.K. Chesterton once wrote; “I read them, I write them; but I do not believe them.” Chesterton put into his beloved Father Brown stories a great deal that he did not believe — exotic crimes, improbable methods, wire-drawn detective work — but also a great deal that he did believe, much of it on the lips of his moon-faced clerical sleuth.

The twist in one Father Brown story after another is that a seemingly unworldly priest is the most worldly-wise of all; the believer in miracles is the most rational, least gullible in the room; the supposedly sheltered religious celibate has the most intimate knowledge and empathic understanding of the ways of human depravity.

“Trust me,” Mark Williams’ Father Brown tells a woman tongue-tied by shame in the pilot episode of the BBC hit series, “there’s not much in my line of work I haven’t heard.” (Season 1 of “Father Brown” is available on North American home video.)

That line, for fans of the source material, is an all-too-rare rare flash of Chestertonian sensibility in a cozy, nostalgic British crime series that, while not without merit, has little in common either with the letter or the spirit of Chesterton’s yarns.

The series is said to be “based on characters” created by Chesterton. The original stories, written over the last quarter century of Chesterton’s life (he died in 1936), were contemporary tales about a London-based country priest who traveled all over the UK and visited Europe and America.

Reasonably settling on the early 1950s as a compromise between Chesterton’s time and our own, the BBC series finds Father Brown engaged in parish work in a sleepy Cotswolds village with a regular cast of quirky characters, giving the series a “Miss Marple” or “Midsomer Murders” vibe.

The English anti-Catholicism regularly satirized in Chesterton’s stories is essentially moot here. Rather than a good-will ambassador of Romanism to Anglican and modernist readers, this Father Brown is a genial representative of enlightened faith to secular postmodern viewers — no bad thing in itself.

At the same time, the show is very much of its cultural moment, with themes of feminist and gay consciousness and the failings of the Church and Christian society woven into the stories. None of this is inherently objectionable, but where Chesterton sought to challenge as well as entertain his audience, the show wants only to be loved.

“I won’t try to convert you,” Brown assures a troubled gay atheist in the first episode.

The wry reply: “Likewise.”

Ironically, Father Brown might almost be said to have helped convert Chesterton himself, who created and initially wrote the character as an Anglican, modeling him after a Catholic priest friend, Rev. John O’Connor. Father Brown also helped to convert the first British actor to portray him, Alec Guinness in the 1954 film “Father Brown” (also known as “The Detective”).

Guinness ideally conveyed Father Brown’s nondescript anonymity and air of abstraction, though he wasn’t physically suited to the role— nor was Kenneth More, who played the priest in 1974 in a 13-episode ITV series that remains the adaptation most likely to please purists (and probably only purists, given its modest production values). Amiable Williams, readily recognizable as Chesterton’s doughy but sharp-minded cleric, is the new show’s best asset.