Sometimes, a period movie comes along at just the right time, during a socio-political moment when its look at past events and themes take on added significance. The new British film “Blue Jean” is one such, exploring as it does the trauma that “Clause 28” caused on the lives of a group of lesbians in late ‘80s England. 

The clause was part of a broader bill introduced by the Thatcher administration under which schools and libraries were not allowed to “promote” homosexuality as acceptable. Analogies with the “Don’t Say Gay” bill signed recently by the Florida governor (and presidential candidate), Ron DeSantis, make the movie’s message all the more relevant.

Our heroine is Jean, a physical education teacher at a Newcastle high school who looks as young if not younger than some of her students, with her pixie haircut and spry physique. While some viewers may chuckle at the image of yet another lesbian gym teacher, the movie humanizes the stereotype with its serious tone and detailed observations of her daily life. We see her effectively coach a netball team, babysit her nephew, play pool with her female friends at a bar, and begin a tentative relationship with the punkish Viv. 

Everything seems to be going well in Jean’s life, and yet there are signs of self-denial and acute anxiety: when radio news talks of the clause, she changes the station; when her sister makes an unexpected visit to her apartment, Viv has to make herself scarce; closeted at school, she keeps conversation with the fellow teachers to a minimum.

The biggest jolt, though, to her sense of well-being arrives in the shape of a new student, Lois, particularly when Jean sees Lois at the local gay bar. Knowing there’s a lesbian student in her gym class not only increases her apprehension that she’ll be “found out,” but also compels Jean to start to second-guess her teaching methods, despite all evidence of consummate professionalism and efficacy. All this occurs while snippets on the radio and television news segments discuss the proposed bill, creating an insidious atmosphere of fear and loathing that leads up to an incident involving Lois and another female student that Jean witnesses.

Rosy McEwen, seen last year in the movie Vesper, brings a Nicole Kidman-like intensity to the role of Jean. She looks like the renowned Australian actress, too. From her subdued apartment in a middle-class neighborhood to her no-nonsense bearing at work, Jean just wants some peace and to be able to live her life as privately as possible, and Ms. McEwen portrays this desire with deft dignity. 

At times, Jean’s aloofness chafes against her girlfriend’s more open personality, and actress Kerrie Hayes is heartbreakingly tender as Viv. Ms. Hayes understands that Viv is just like anyone falling in love – needy, curious, playful – despite the character’s butch exterior of tattoos, piercings, and a shaved head.

Newcomer Lucy Halliday convincingly plays teenage Lois as both confident in who she is and as someone who is still trying to figure things out. Indeed, the actress reminded me of another lesbian teen character making her way through school injustices — Tammy Metzler in “Election” — though “Blue Jean” doesn’t share that movie’s satirical tone.

What the movie does exceedingly well is demonstrate how paranoia sets in when homophobia is encouraged and institutionalized. First-time filmmaker Georgia Oakley depicts the psychological toll on Jean through several stylistic elements, not least of which is the use of myriad shades of blue to denote the character’s lowkey depression. Ms. Oakley also revives a hoary device when she shows Jean in a head-under-water bathtub scene, instilling the visual cliché with vitality by grounding the scene in the character’s fragile mental health and by filming her in a fetal position. 

With its ominous sound design and nightmarish sequences, the movie nearly becomes the latest example of the psychological horror genre. Thankfully, the filmmakers are more interested in everyday terrors, and when Jean betrays Lois after the girl is falsely accused of assault, and then Viv breaks up with her, a harrowing moral reckoning is in order for the character. A couple moments of levity occur as well, such as in an extraordinary scene in which Jean matter-of-factly admits she’s a lesbian at a child’s birthday party, only to laugh-cry afterward while wild horses prance nearby. It’s almost camp.

Early in the film, Jean says, “Not everything is political,” and yet throughout its succinct runtime, “Blue Jean” reveals, methodically and powerfully, the deep naivety of that statement. And yet it’s a sentiment this masterly movie recognizes we’d all like to believe.