He was born in Liverpool, the son of James Danvers (1855-1915), a well-known singer with the D'Oyly Carte Opera Company, and his wife Annie (née Dobbs).

At the time of his birth, they were appearing in a touring show of Gilbert and Sullivan's The Mikado, with James in the title role, and gave their son the operetta's name.

He appeared in revues, variety shows, pantomimes (often as "Buttons"), and musical comedies, and performed in New York as well as throughout Britain.

[2] In 1942, Pat Hillyard, Assistant Director of Variety at the BBC, instructed all programme producers to scrutinise Danvers' performances, to make sure that he did not "slip anything in on the night".

[3] From 1948, described as "Always Merry and Bright", Danvers toured as part of Don Ross's successful show Thanks for the Memory,[4] and appeared in that year's Royal Variety Performance.