WHEN the Pretty Things play their final show with electric instruments in London on December 13th, 55 years after their formation, few in attendance will have thought to consider the group’s influence on contemporary hip-hop. What could an ancient British rock band have to offer the bleeding edge of black music? Just one thing. Almost exactly 50 years ago, the Pretty Things invented the rock opera when they released “S.F. Sorrow” and the themed album—the hip-hopera, if you will—has become increasingly prevalent in rap and R&B.

Though rappers have indulged in song sequences for many years, they were often story arcs about the protagonist’s success (or otherwise) in crime, such as Jay Z’s “American Gangster” (2007). Now the records are increasingly ambitious in scope. In September, Lupe Fiasco (pictured) released “Drogas Wave”, a 100-minute album spanning different musical styles. Its concept would have attracted approving nods from any number of hirsute, loon-panted prog-rockers in the 1970s. “It’s about a group of slaves on a slave ship on their way to Africa to the West Indies and they are thrown off the boat,” Mr Fiasco explained. “But they didn’t die. They stayed alive and they lived under the sea. And they dedicated their lives to sinking slave ships—so they became this super, underwater force against slavery.”

Noting work by Beyoncé (“Lemonade”), Big Sean (“I Decided”), Kid Cudi (“Man on the Moon: The End of the Day”), Kendrick Lamar (“DAMN.”) and others, Noisey, a popular music website, observed that “the rap and R&B sphere has adopted the concept album as the ultimate artistic goal over the course of this decade and made this obsolete genre a championship belt to be claimed”. The article took no account of the fact that hip-hop was also chosen to tell the story of one of America’s founding fathers in “Hamilton”.

The first wave of concept albums, from the late 1960s until the mid-1970s, were rock music’s flight from frivolity into portentousness (the sleeve notes to Yes’s “Tales From Topographic Oceans” claimed, implausibly, that it had been inspired by “a lengthy footnote on page 83 of ‘Autobiography of a Yogi’”). Phil May, the lead singer of the Pretty Things, expresses a certain disappointment when told that the story of “S.F. Sorrow” is impossible to follow. “I know a lot of people who don't listen to lyrics. They have no idea what the story is about. And if you're a lyricist, that's really important to you,” he says. Dick Taylor, his bandmate, puts him in his place: “I couldn’t follow it either.” In truth, Mr Fiasco’s “Drogas Wave” is barely more comprehensible without thoroughly annotated lyrics to hand.

Why has the concept album taken such a hold of hip-hop? “At a time when there is more freedom for artists to release as much music as they want directly to streaming services, and many hip-hop artists release several albums or mixtapes or EPs a year, I think that’s resulted in a raised impetus to make specific albums feel important or eventful,” says Al Shipley, an American hip-hop commentator. Simran Singh, a lecturer in global hip-hop at Southampton University, suggests that “the internet has created a space for the avant-garde and therefore, conceptual”.

But it is odd that it has become the highest statement of achievement just as the album has ceased to be the lingua franca of music consumption. Rolling Stone reported that on Drake’s “Scorpion”, the most popular album in America this year, six out of its 25 songs accounted for 82% of its total streams. Looking at the Spotify figures for Childish Gambino’s “Because the Internet”, you can see that while its most popular track, “V.3005”, has nearly 290m streams, most people simply stop listening after that. The eight tracks that precede it have healthy listening figures, while the ten that succeed it hover around 20m streams. It is no longer a case of people not understanding the concept; most of them don’t even hear it out.

In the second half of the 1970s, the concept album was banished to the margins by punk, and by the bands inspired by that style’s brevity and directness. When the golden age of the hip-hop concept album passes, it looks more likely that it will be technology that kills it. In the meantime, if you hear of a rapper enthusing about “Autobiography of a Yogi”, be very sceptical indeed.