THE film Getting It Back: The story of Cymande (Cert. 12A) is a documentary about the fall and rise of a 1970s black group of musicians from Balham and Brixton. It’s also the story of prophets without honour in their own country: how Windrush generation children experienced both acceptance and rejection.

Believing that the Creator put them on the earth for a reason, Cymande pioneered a remarkable sound, nyah-rock, which aficionados would recognise as a fusion of Caribbean jazz, reggae, funk, and soul, together with R&B, rare groove, gangsta drum and bass, hip-hop, and house music. This debut feature from the director Tim Mackenzie-Smith prevents the usual mishmash of talking heads peppered with musical snatches by providing contextual archival news clips.

Publicity accompanying the film, Blu-ray disc, and Cymande’s forthcoming tour describes these players as the greatest band you’ve probably never heard of, but whose music you may well know. A huge success in the United States, they were the first UK group to top the bill at the Apollo Theatre, Harlem, and at other venues, where they appeared alongside the likes of Al Green. The film clearly demonstrates that Cymande continue to be a stylistic influence on younger musicians.

Yet it was because they were getting so little attention back home that heavy-heartedly they broke up in 1974. Their story is representative of the situation facing many West Indians. Newsreel extracts feature some shockingly racist hostility to them. On television, a black contributor expresses views that struggle to be heard in contemporary debates about immigration: “In the same way that the Englishman has believed that he had a right to go out and civilise Africa, I believe that we are here to teach you again how to be human.”

Cymande, through their music, felt that they were assisting this process. Songs such as “Changes”, from the album Promised Heights, combine clear-sighted appraisal of institutional discrimination (“Lord it gets harder, these times,”) with hope that they “are changing faster than before. . . All that we do should clearly show That when the need is there love grows.”

The effect that church teaching had had on such lyrics is neatly illustrated by a shot of a plaque bearing the words “Christ is the head of this house, the unseen guest of every meal, the silent listener to every conversation”.

Interesting in itself is how the band reassembled. Getting It Back tells us it was through church that one of the band members was persuaded to resume his God-given talent for playing the saxophone. He hadn’t touched the instrument for forty years. Beating Village People to it by several years, the players have an implicit belief that nobody can stop the music — this particular music. It is limitless, transcending social and generational divisions. It is what gives us hope.

Cymande’s symbol is named after the calypso word for dove, thereby endorsing their songs of peace and love. Strangely, there is no overt reference to the band’s 2015 album A Simple Act of Faith, which features, if not exactly hymns, then arguably sacred songs. Its title track is just one of several to assert Cymande’s belief in the divine supremacy of love.

Now in cinemas, and available digitally on BFI Player and released on Blu-ray by the BFI on 19 February: from the BFI Shop (phone 020 7815 1350) or via www.bfi.org.uk/shop