Fifty years ago today, on 5 September 1976, an unknown young band called the Clash played only their fifth-ever gig, supporting the Kursaal Flyers and Crazy Cavan 'n' the Rhythm Rockers at London's Roundhouse. The performance is historically significant because it was one of the earliest public appearances of a band that would go on to become one of punk's most influential acts, despite being so obscure at the time that they were not even listed in newspaper adverts for the show.

A surviving audience recording captures the crowd's frosty reception, with frontman Joe Strummer trading insults with hecklers after the audience refused to stand up, at one point launching a profanity-laced tirade against one attendee. The band, then featuring Strummer, Mick Jones, Keith Levene, Paul Simonon and Terry Chimes, played an early set including songs later dropped from their repertoire, alongside an embryonic version of "I'm So Bored With the USA" (then about a girlfriend rather than a country) and set-closers "London's Burning", "What's My Name" and "1977", the latter featuring Strummer's prophetic declaration rejecting Elvis, the Beatles and the Rolling Stones as rock's future.