Bernice Summerfield was originally introduced in the New Adventures series of Doctor Who spin-off novels, as a companion for the Seventh Doctor. When Virgin's license to publish Doctor Who fiction was not renewed by the BBC in 1997, Virgin decided to continue the series as Bernice Summerfield books, without any mention of the Doctor or any Doctor Who branding.
Big Finish Productions took over the production of Bernice Summerfield stories after the closure of Virgin's fiction branch in 1999.