Neve wants to believe it when she says it. She especially wants the person she’s talking with to buy in.

“I’m a proud Black woman,” she says, not even convincing herself. “PROUD.”

But we’ve already seen her immersion in white British suburbia — Castle Combe, is it? We’ve heard Neve practice her posh pronunciations in the vanity mirror before heading out. We’ve caught her donation-shaming a neighbor into supporting her latest cause and overheard another neighbor, a friend, “compliment” her by saying she’s “practically one of us.“

She’s married well, with two teens in the local private school, where she’s taken on classes and assistant head-mistress duties, without ever locating her “references,” her boss jokes.

She frets over wigs, the pricey gloves that she wears to drive the Range Rover, considering every word and the appropriate received pronunciation way of saying it. Even her walk seems studied.

When you’re Black practically “passing” for white in your little corner of Brexitania, every day’s a little more “Stepford” than the last.

And God forbid she see a Black face in town. That’s most triggering of all. Neve is certain, on a gut level, that “The Strays” will be her undoing.

Actor-turned-writer/director Nathaniel Martello-White and his star, Ashley Madekwe of Brit-TV’s “Secret Diary of a Call Girl,” cook up a fine, paranoid thriller about race, the many shades of racism and “appearances.”

That’s what Neve struggles to maintain even as she becomes unhinged by seeing a Black man (Jordan Myrie) in town, and then as the new custodian at her school. It’s a good thing she hasn’t caught a glimpse of him with a young Black woman (Bukky Bakray). Because that, we’re sure, will really set her off.

Neve, her white husband (Justin Salinger) and kids (Samuel Paul Small, Maria Almieda) refer to themselves as “a Black family.” But it’s easy to see signs they’re playing that down. Son Sebastian may play basketball (like a British actor). But he’s keen to minimize the racist bullying he encounters at school.

When daughter Mary comes home with her blondish hair in braids, Neve visibly quakes. Fair-skinned, and all this effort to “fit in” and look white, and the kid does this.

As Neve sees Black people among them, as nobody else seems to notice them (at first), as taped black stick figures turn up on the mirror on her Range Rover, we’re allowed just enough time to wonder just how much of this is in her head, and if she’s over-reacting to a perceived “threat.”

She’s hellbent on not taking in “strays.”

Martello-White peppers his script with the death-by-a-million-cuts racial indignities a Black minority faces even after assimilating into a white society — dinner party “friends” who tactlessly quote some new dog-whistling pundit who “dares” to revive “white flight” as a cultural phenomenon.

Interviewing for a job, the would-be custodian knows to read the room and talk up Liverpool FC to the head master doing the hiring, who breaks the ice with a tone-deaf “The only color that matters — TEAM colors!”

Liberal do-gooderism is chided as a benefit for “the less fortunate” comes unraveled when those “less fortunate” show up.

The third act resolutions to the mystery, and sudden turn towards violence, are more strained and limiting than one might like. But Madekwe plays up Neve’s calculating ways, and the added math she does to identify a perceived menace to her world.

And the smart, subdued finale is the only one that we’d believe and accept — logical, and damning and thought-provoking, not unlike the thriller than precedes it.

Rating: TV-MA, violence, profanity

Cast: Ashley Madekwe, Justin Salinger, Jordan Myrie, Samuel Paul Small, Maria Almieda and Bukky Bakray.

Credits: Scripted and directed by Nathaniel Martello-White. A Netflix release.

Running time: 1:40