The group’s fourth studio album, it was the first by a new line-up that included Simon House on synthesizer, Mellotron and electric violin; absent were Robert Calvert, who had previously contributed lyrics, vocals and spoken word interludes, and Dik Mik, who provided electronic effects.
The album’s title was a nod to Edvard Grieg’s “In the Hall of the Mountain King“ and to a Portobello Road cafe called The Mountain Grill (now closed), frequented by the band in the early 1970s. The cover of a derelict spaceship in the mists of an alien lagoon was painted by the band’s regular artistic collaborator, Barney Bubbles. The rear cover was by space artist David Hardy.
The record featured hard rockers like “The Psychedelic Warlords (Disappear in Smoke)“ and “Lost Johnny“ (subsequently recorded by bassist Lemmy’s post-Hawkwind band Motörhead and also by co-writer Mick Farren with his band the The Deviants), psychedelia such as the heavily-phased "