John Deacon was the only Queen member never to sing lead vocals on a studio recording.
Deacon joined Queen in 1971, completing the classic four-man lineup with Freddie Mercury, Brian May and Roger Taylor. Although best known as the bassist, he also played guitar, keyboards and synthesizer on various Queen recordings. His songwriting produced major hits including “You’re My Best Friend” and “Another One Bites the Dust.”
Despite writing songs that became international successes, Deacon generally gave the lead vocal parts to Mercury. The other three Queen members all sang lead on studio tracks: Mercury was the principal singer, May led songs such as “’39” and “Sail Away Sweet Sister,” and Taylor sang lead on tracks including “I’m in Love with My Car” and “She Makes Me (Stormtrooper in Stilettos).”
The wording matters: Deacon did participate in live backing vocals and is associated with occasional disputed or minor studio vocal contributions, but he never took a lead vocal on a released Queen studio track. That is why the answer is John Deacon, not Roger Taylor, who was Queen’s other prominent songwriter-singer.