Atomic Rooster

Atomic Rooster was an English progressive rock band, originally composed of former members of the The Crazy World of Arthur Brown. Throughout their history, keyboardist Vincent Crane was the only constant member, and wrote the majority of their material. Their history is defined by two periods: the early-mid-1970s and the early 1980s. Their genre in music is difficult to define, since they went through radical changes in very short times during the life of the band. However, their best-known era represented a more hard rock/progressive rock sound, exemplified by their only hit singles, "Tomorrow Night" (UK No. 11) and "The Devil's Answer" (UK No. 4), both in 1971.

source: Wikipedia