Recording ran from July to September 1971 in Trident Studios. In addition to the band and Anthony, Robin Cable, David Hentschel and Ken Scott helped with engineering. The first tracks to be recorded were "Theme One", a cover of the George Martin composition used as the original closing theme to BBC Radio 1, and "W", which was ultimately left off the album. The music, particularly "A Plague of Lighthouse Keepers" was recorded in short sections between two and five minutes, which were later edited together. In addition to Hammill's original suite, Banton contributed the "Pictures/Lighthouse" section, an Olivier Messiaen-influenced organ piece, Evans wrote "Kosmos Tours" around a short piano riff, and Jackson wrote the music to the closing theme, "We Go Now". The piece was edited together by Banton and Anthony towards the end of the session. Banton used an effect called a "psychedelic razor", a customised tape recorder that could rewind and record simultaneously. The device appealed to the band's sense of humour. At one stage, every tape machine in the studio had to be used for mixing.