Progressive rock trio Quatermass formed in 1969, comprising bassist/vocalist John Gustafson, keyboardist Pete Robinson, and ex-Episode Six drummer Mick Underwood. Underwood had previously spent time with Ritchie Blackmore (Deep Purple, Rainbow) in the Outlaws, in addition to cutting his teeth with Shadows bassist Jet Harris and an early incarnation of the Herd; Gustafson had a background in the Merseybeats and the Big Three.
Quatermass issued their lone LP on Harvest in 1970. Despite being regarded as a fine release by the label, it didn't do much commercially, and the group broke up by the end of the following year. Underwood later joined Strapps, another Harvest act that enjoyed a longer lifespan. Both he and Gustafson eventually played with Ian Gillan at separate times, and Gustafson also went on to play on the third, fourth, and fifth Roxy Music records. Robinson also remained busy as a session musician.