"We want the Johnny who danced with this chick!"
A young woman gets murdered. The police inspectors assume she's Caucasian-- until her obviously biracial brother arrives. The attempts to solve the mystery get hampered by racial attitudes-- and shaped by the fear that racism somehow contributed to young Sapphire's death. Suspicion falls, in particular, on her white boyfriend, who didn't know her background when he met her.
Sapphire features the range of prejudices and racial attitudes present in 1959 England, including virulent racism, casual racism, acquiescence to popular prejudice, internalized racism, antiracism, and harmonious friendship. As in the more famous In the Heat of the Night, the mystery's solution is less important than the issues addressed during the investigation. Of the two movies, Sapphire has greater nuance and fewer awards clip moments.
The film also presents some unquestioned prejudices. Sapphire's lack of a room-mate and love of nightclubs get coded, pretty clearly, as evidence that she's the kind of woman whom we might expect would turn up dead some day.
Older British films love their eccentric bit-parts, and a few get their moments in this movie. Freda Bamford plays a butch female constable who gets asked for input on the victim's lingerie. Robert Adams gives a memorable performance as a West Indian man known as "Horace Big Cigar."
The solution eventually arrives, after numerous red herrings, personal growth by the detectives, and some very dubious handling of evidence. I don't know if that last point represents actual police work at the time, or artistic license. Sapphire may not be most memorable film England produced in the late 1950s, but it provides viewers with a minor mystery, some well-performed melodrama, and a glimpse into a bygone era that was less genteel than some people want to imagine.