Here’s a bracing blast from the past, a time capsule of Jamaican London and the prehistory of hip hop via its dub reggae birth parent.

Franco Rosso’s “Babylon,” a 1980 near-classic that had little in the line of a real release, back when new, is a cult film that’s been cleaned up, restored and fully subtitled for theatrical release.

Because unless you be Jamaican mon, Cho, it be tuff to understan’. We all bomboclaat if we’re not from the Island when it comes to the gloriously musical, dense patois spoken there and here.

Rosso’s film captures a slice of London’s Thatcher era subculture, transplanted Jamaicans working, loving, hustling and — in this film’s circle — hunting for that “fresh” sound, that record with “not one scratch, mon.” Only a tune — “Straight from the J” — that no other DJ has scratched for use as a backing track to sing/rap to will do for the likes of Ital Lion.

That’s the collective fronted by Dreadhead (Archie Pool), with guys like the hothead Beefy (Trevor Laird), trusted lieutenant Errol (David. N. Haynes) and soldering iron wizard Scientist (singer/composer Brian Bovell) all supporting singing mechanic Blu (Brinsley Forde) as they pursue dub battle victories that trace a path to pop stardom, riches and glory.

Not that this “pursuit” is what the film is about. This “life” that Rosso slices is of the world these guys live in — rough hustles and endless hassles by The Man, anti-assimilating anti-social behavior exacerbating the pervasive racism they face every day in every way. Cy

Blu lives at home with a school-skipping little brother his mother (Cynthia Powell) orders Blu to ride herd on.

Blu’s a mechanic who long ago used up his excuses for why he’s late.

“I don’t like monkeys who get too clever in my garage,” his racist boss gripes. Best pal Ronnie (Karl Howman) may be able to get away with not showing up, back-talking. That’s because he’s white.

Ronnie hangs with the Ital Lion crew, their amusing token Cockney reggae expert who doesn’t fit in and gets a dose of what “your kind, Mon. Your f—–g kind” is doing to keep these guys down.

Rosso follows put-upon Beefy as he is disrespected by one and all, only to lose his temper and pull out a knife. His temper and the knives grow through the course of “Babylon.” Dude pulls out a machete at one point.

The hard edge is rubbed off somewhat by many comic moments — Dreadhead haggling with Fat Larry, an Indo-Jamaican producer/hustler who is always trying to max out the sales price of whatever tune he’s got “straight from the J to me!”

“I hear dem tune a good two year…When come dot release, ‘pre-war?'”

The guys get into it with all manner of working class locals, who trot out “jungle bunnies” with their “bloody jungle music” when the arguments start.

The objects of their racist contempt don’t help matters by carrying out muggings, petty theft and vastly increasing the traffic of ganja in 1980 London.

Beefy, at one point, steals a briefcase-sized video camera. But he’s either ahead of the times or clueless. He forgets the SUITCASE sized recorder unit. They’re always stealing speakers from schools, rounding up the pieces to a massive sound system that they use for their performance/battles.

Laird, Forde and Pool give dazzlingly unaffected performances, and Haynes and Howman hold up their end of the picture, too. Every bit part feels documentary real in its execution.

It’s dated, sure, a piece of pre-assimilation history built on music that hasn’t been in fashion for decades and fashion that never quite become “The Fashion.”

“Look, Mon, he’s a walkin’ flag of Ethiopia!”

The story isn’t anything to put on a resume.

But “Babylon” brims over with life in ways that few films of recent vintage could manage, a movie-moment that remembers when “One Love” was enough to end any argument and calm any troubled waters.

MPAA Rating: unrated, violence, drug use, profanity

Cast:  Brinsley Forde, David N. Haynes, Trevor Laird, Beverly Michaels, Victor Romero Evans, Archie Pool, Cynthia Powell and Karl Howman

Credits: Directed by Franco Rosso, script by Franco Rosso and Martin Stellman. A Kino Lorber release.

Running time: 1:36