Triumphantly, London Calling builds on the band’s love of reggae. It is steeped in the bass-heavy, trance-inducing vibes of Afrocentric 1970s reggae albums such as Satta Massagana, by The Abyssinians, and Culture’s Two Sevens Clash. A cover of Junior Murvin’s 1977 reggae hit Police & Thieves had appeared on the Clash’s debut album, and the gruff-voiced Jamaican DJ-singer Prince Far I was mentioned on their 1978 single Clash City Rockers.

The standout reggae-inflected track on London Calling, Guns of Brixton, written by the band’s bassist, Paul Simonon, alludes to the Jamaican outlaw Vincent “Ivan”, or “Ivanhoe”, Martin, who terrified the island’s capital, Kingston, in the 1940s with his armed hold-ups, until a police manhunt left him dead. To Simonon’s romantic imagination, Ivan was a Caribbean Ned Kelly who eluded capture even as he taunted the authorities.

The outlaw imagery of guns and gang warfare was naive romanticism. In 1977 Strummer had accompanied Jones to Kingston, only to find a frightening place on the edge of bloodshed. (“I went to the place where every white face is an invitation to robbery,” Strummer sang on Safe European Home, an oblique comment on mid-1970s Jamaica.)

Nevertheless, London Calling’s badland balladry sat well with punk’s avowed anti-establishment credentials. Wrong ’Em Boyo, a ska jolly-up sired out of an old New Orleans tune, tells of the 19th century African-American folk hero Lee Shelton, aka Stagger Lee, who shot dead a white man. Revolution Rock, another ballad, draws from the rude-boy identity of Perry Henzell’s cult Jamaican film The Harder They Come, from 1972, which depicts the bullet-scarred life of an Ivan-like outlaw as he struggles to survive in the ganja yards and urban alleys of western Kingston.

On the cover of London Calling was Pennie Smith’s now famous photograph of Simonon smashing his bass guitar on to the stage of the New York Palladium. Although out of focus, it suited the band’s ragamuffin image – and recalled The Who’s auto-destructive pop art. Although the Ramones had released a double live album of punky three-chord anthems in 1977, the idea of a double album was essentially hostile to punk’s DIY ethos of self-motivation and singles-only output. While some British critics objected to The Clash’s alleged commercialism – one negative review punned on the title of the band’s previous album, Give ’Em Enough Rope, with the headline Give ’Em Enough Dope – American critics on the whole applauded the music’s immense breadth and “primal energy”, as the New York Times put it. Overnight, London Calling sold two million copies and propelled The Clash, all guns blazing, into the 1980s.