Gryphon were a British progressive rock band of the 1970s, notable for their unusual sound and instrumentation. Multi-instrumentalist Richard Harvey and his fellow Royal Academy of Music graduate Brian Gulland, a woodwind player, began the group as an all-acoustic ensemble that mixed traditional English folk music with medieval and Renaissance influences. After their self-titled debut, they expanded their sound to include electric guitars and keyboards as well as wind instruments, such as bassoons and crumhorns, not often found in rock music. Gryphon's music often sounded as much like rural English folk or Renaissance chansons as it did rock, at least on their early recordings. After their third album (Red Queen to Gryphon Three) and the subsequent tour as a supporting act for Yes, their instrumentation became more conventional and the use of non-standard instruments was reduced. Fans and critics generally regard Midnight Mushrumps and the all-instrumental Red Queen to Gryphon Three as their finest albums.

In 1974, the group's publicist Martin Lewis arranged for the band to be commissioned to write and record the music for a major stage production of Shakespeare's The Tempest at Britain's National Theatre directed by Sir Peter Hall. It opened at the historic Old Vic theatre in April 1974. The music the band wrote and recorded for the stage production inspired the 21-minute fantasia "Midnight Mushrumps" (a phrase heard in The Tempest) which became the title track of their second album. Following the successful premiere of the play and acclaim for its music, Lewis arranged for Gryphon to give a Sunday evening concert at the Old Vic in July 1974 - the first-ever rock concert held at Britain's National Theatre. At the concert the band performed "Midnight Mushrumps". The concert was considered a major breakthrough for progressive music. Rumours have abounded that there are audio tapes of the fabled concert but none have yet surfaced.

Members
Brian Gulland — Bassoon, Crumhorn, Recorder, Keyboards, Vocals
Richard Harvey — Recorder, Crumhorn, Mandolin, Keyboards, Vocals
David Oberlé — Drums, Percussion, Lead Vocals
Graeme Taylor — Guitars, Vocals (through Raindance)
Philip Nestor — Bass guitar, Vocals (Midnight Mushrumps and Red Queen to Gryphon Three)
Malcolm Bennett — Bass guitar, Flute (Raindance)
Jonathan Davie — Bass guitar (Treason)
Bob Foster — Guitar (Treason)