Written about British fascist Oswald Mosley, the song features what AllMusic described as a "slow, slinky [and] sinister" melody.

The song expressed Costello's anger after seeing former British Union of Fascists leader Oswald Mosley interviewed on television, attempting to deny his racist past.

[1] In the liner notes to the Rhino edition of the album, Costello writes: "Less Than Zero" was a song I had written after seeing the despicable Oswald Mosley being interviewed on BBC television.

[2]On his first visit to the United States, Costello found that American audiences did not understand the song, writing in his 2015 autobiography, Unfaithful Music and Disappearing Ink: "I'm not sure if anyone in Cleveland had ever heard of Oswald Mosley or gave a damn about him when we played 'Less Than Zero' that night.

"Less than Zero" fits in with a number of others on early Costello albums that deal with themes of fascism and totalitarianism, which also include "Night Rally" from This Year's Model and "Goon Squad" from Armed Forces.

[1] Deming describes the song as "controversial, audacious, and highly effective" as well as "a truly remarkable debut.