The "Thompson Submachine Gun" or "Tommy Gun" for short, is the typical gun from the American Prohibition era, where it was used by both the police and gangsters. A series of rapid snare drum beats by Topper Headon mimics the "rat-ta-ta-ta" sound of them, and were suggested by him during recording. It was after recording the drum tracks for "Tommy Gun" in one take each time with no mistakes that producer Sandy Pearlman labelled Headon "The Human Drum Machine."
In the album liner notes to Clash on Broadway, Joe Strummer explained that he believed terrorists probably enjoy reading about their killings in the news, just like musicians or movie stars like to read reviews of their works. In a discussion with NME's Gavin Martin, he described thus: "I was saying us rock 'n' rollers are all posers and egomaniacs, but we know that terrorists are as bad, or worse than we are. They definitely love to read their own press... I know they dedicate their life to a cause, but they're always posing for pictures."
"Tommy Gun" attracted some controversy in some quarters as its topic of international terrorism was a continuation of singer Joe Strummer's recent flirtation with terrorist chic. In early 1978 he made controversial comments appearing to support the Red Brigade of Italy (of whom he often wore a red 'Brigade Rosse' T-shirt in support of when playing live, including at their famous Rock Against Racism show in 1978) and Red Army Faction of Germany, and many Irish fans voiced displeasure when he wore a 'H-Block' T-shirt in solidarity with IRA prisoners held there, particularly those involved with the families of those killed on the Falls Road attacks.
This was The Clash's first Top 20 hit in the UK, peaking at #19. It was first debuted in London in late 1977 and remained a firm favorite live, only being dropped for some time in 1979.
Longtime friend of the band Don Letts filmed the video, his first of many for The Clash. He shot footage during the soundcheck to a show at the Harlesden Roxy in October 1978.