The hardboiled gumshoe likes his cigars skinny, his razor dull, his women curvaceous and compliant and his sex with spanking.

Must be British.

A meandering, dawdling murder mystery two and a half bloody hours long? Must be a TV movie edited down from a British TV series.

There’s something almost but not-quite-laughable about “Silent Hours,” a plodding, newfangled/old-fashioned thriller about a lady killer Royal Navy vet who swears that all these women who keep getting cut up are not dying by his hand. Because he’s not that kind of lady-killer.

Women throw themselves at John Duvall (James Weber Brown of “Coronation Street” and “Detectorists”), showing off their exotic lingerie and indulging his passion position from the dog-fancier chapter of the Kama Sutra.

Also very British?

“Silent Hours” — it takes its title from “Navy slanguage” for nighttime on a ship — has lots of exotic underwear, lots of sex and a dash of death. It’s built around a hero with “a past” and absolutely no scruples about whom he beds.

In 2002 Portsmouth, the quintessential “Navy town,” Duvall spies on cheating spouses for a fee. One client might be a fish factory owner. Another is a ship’s commander (Hugh Bonneville).

We meet him in therapy where a shrink (Indira Varma) questions his Navy record and his “voyeuristic” line of work and wonders what it’s done to him. As the story jumps back and forth between “sessions” and his detective work on the docks, ships, seaside and old fortifications of Portsmouth.

I mean, if you could stage a meeting with a “source” on an old gun emplacement nibbled over by llamas, wouldn’t you?

As clients, or their wayward wives, start dying, Duvall starts snooping around, even if he’s not letting anybody see the concern setting in. The coppers (Dervla Kirwan) smile and start looking at Duvall as a suspect.

“Are you withholding evidence from a police murder investigation, Mr. Private Peeping Tom Detective?”

Maybe. As the bodies pile up — including Duvall’s girlfriend (Elizabeth Healey), he starts to sweat. Well, he would, if it wasn’t so damned cold.

Turning a three-episode TV series into a movie isn’t unheard of. But this editing job results in a lurching, convoluted thriller that never gets on its feet and up to speed.

Here’s a newspaper reporter “source,” and an old friend whose radio expertise might help decipher an old answering machine tape. Introduced and forgotten. There’s an old girlfriend who gets “flashes” and senses things from people and objects. Supernaturalism? On top of everything else?

The film has a vivid sense of place, with all the gulls and crisp mornings and fish.

But the “Portsmouth Ripper” case that should grip the city never delivers suspense or much that I’d call a mystery, even though it is a favorite British TV genre and thus, they should be good at it. All involved got lost in the salacious — sex and sex and sex — and never come up for air.

“She certainly has a thing for naughty underwear.”

“Silent Hours” is a lot of stuff about Naval procurements, undersea stashes, real estate, troubled pasts and double entendres and women throwing themselves at a grizzled, 50ish retired sailor.

Very film noir, to be sure. But not set in 2002. Maybe in 1952 this would fly.

Rating: violent imagery, sex, profanity

Cast: James Weber Brown, Susie Amy, Dervla Kirwan, Indira Varma and Hugh Bonneville

Credits: Scripted and directed by Mark Greenstreet. A Gravitas Ventures release.

Running time: 2:36