Thirty Rockefeller Plaza was abuzz in the lead-up to Saturday Night Live’s third season Christmas episode. Taking nothing away from that Dec. 17, 1977 show’s host, 80-year-old Miskel Spillman, the winner of SNL’s first (and, to this point only) “Anyone Can Host the Saturday Night Show” contest, it was the announced musical guests who had NBC executives and SNL cast and crew members alternately tingly or petrified, depending on the generation.

Britain’s Sex Pistols, riding a tsunami of controversy, critical acclaim and vocal outrage following the Oct. 28, 1977 release of their debut album, Never Mind the Bollocks, Here’s the Sex Pistols, were all set to embark on what would become the band’s one and only U.S. tour, complete with a New York stop to perform on Saturday Night Live. The sketch show, then riding high itself as a counterculture-minded alternative to stale TV comedy, already had a history of booking musical outliers. Sun Ra, Frank Zappa, Loudon Wainwright III, Kinky Friedman and Tom Waits were among those introduced to much of the American viewing public for the first time. But SNL hadn’t truly embraced the swelling punk music scene, with Patti Smith’s raucous season 1 appearance (in which the unshaven singer spit the lyrics “Jesus died for somebody’s sins but not mine” just as the show clock clicked over onto Easter Sunday) being the nearest example.

But the Pistols were the real deal, a scabrous, unmanageable, frequently banned clutch of punks who, the year prior, caused a drunken, profanity-laced scandal on a live London interview program. So executives, censors and no doubt many of the SNL staff were anticipating trouble—and huge ratings. Sadly for viewers looking to see just how far the Sex Pistols would go on live U.S. TV, the planned appearance was scuttled, by the United States government.

Watch Sex Pistols’ Infamous 1976 U.K. TV Interview

Citing the criminal histories of the band’s four members — Johnny Rotten, Sid Vicious, Paul Cook and Steve Jones — ranging from drug offenses to assault, the U.S. embassy in London refused Pistols’ manager Malcolm McLaren’s visa applications for the Sex Pistols. Amidst the group’s chaotic and widely disputed history, some have debated whether the Pistols simply wanted to complete their “Never Mind the Bans” mini-tour back in England (the band did play a Christmas Day benefit show in the English town of Huddersfield), or whether McLaren simply botched the visa process in advance of the planned U.S. tour. Then there’s the not-so-farfetched theory that the band’s infamous and incendiary material (often lobbed at British establishment figures, right up to Queen Elizabeth II) informed officials’ decision to not grant waivers to the band members for their criminal pasts, as had been done for higher-profile British performers like the Rolling Stones’ Keith Richards and Mick Jagger.

Still, the Saturday Night Live appearance was off, with the 23-year-old Elvis Costello, then in New York on his own U.S. tour, taking the Pistols’ place at the last minute, and delivering his own middle finger to NBC and his own record company’s mandates. (New York punks the Ramones were SNL’s first choice of fill-in, but, true to form, guitarist Johnny Ramone reportedly replied, “We don’t substitute for nobody.”) Famously stopping his bandmates, the Attractions, a few bars into the Colombia Records-chosen “Less Than Zero,” with an abrupt, “I’m sorry, ladies and gentlemen, but there’s no reason to do this song here,” the bespectacled frontman directed the band to instead play the rousing “Radio, Radio.”

Watch Elvis Costello’s ‘Saturday Night Live’ Performance

While hardly the barrage of expletives one imagines the Sex Pistols had in store for the SNL audience, Costello’s song was still a scathing condemnation of corporate media. Meanwhile, Attractions’ drummer Pete Thomas appeared onstage in a hastily acquired t-shirt reading “Thanks, Malc,” a suitably snotty jab at McLaren for giving the band such a big break. (Speaking of middle fingers, it’s reported in some circles that SNL head honcho Lorne Michaels spent the entirety of the song flipping Costello the bird before eventually banning the singer from the show for a decade.)

As for the Sex Pistols, cooler heads ultimately prevailed, with the band being granted entry to the U.S. in time to belatedly make the rounds of some especially hostile Deep South venues — reportedly chosen by McLaren to provoke hostility and generate further publicity. Bassist Vicious, already a volatile heroin addict at age 20, indeed provoked plenty of both, lashing out at audiences, simulating sex acts onstage and, in one infamous incident, smashing his guitar over an audience member’s head. A January 1978 gig at San Francisco’s Winterland Ballroom was to be the Sex Pistols’ last, with singer Rotten, fed up with the whole circus surrounding the band, taunting the crowd after the brief show, asking, “Ever get the feeling you’ve been cheated?”

It’s difficult to say what, exactly, Saturday Night Live and its viewers were cheated out of thanks to the Pistols’ no-show. Never reliable at the best of times, it’s more than likely that the lure of 1970’s New York nightlife and the temptation to cement their cross-continental punk cred would have seen the Sex Pistols causing enough of a scene that the already nervous NBC executives would have gone to commercial mid-number. (As nearly happened upon Costello’s unvetted song-switch.) And while Costello’s stunt was itself one of the most punk moments in the live show’s history — the rocker eventually recreating the incident for SNL’s 1999 25th Anniversary Special, interrupting the Beastie Boys to once more play “Radio, Radio” — the reaction to this relatively unknown Brit’s rebellious act was greeted with more confusion than outrage from the live audience.

For perhaps the closest approximation of the sort of debacle the Sex Pistols’ 1977 appearance could have caused, a peek ahead to the Halloween 1981 guest spot of L.A. punk provocateurs Fear might offer some clues. Championed by former cast member John Belushi, Fear’s two-song set (of typically button-pushing songs “Beef Bologna” and “New York’s Alright if You Like Saxophones”) was accompanied by thrashing, slam-dancing fans imported for the occasion, resulting in NBC pulling the plug, plus a widely-disputed amount of in-studio damages.