Engineer Andy Johns on recording and mastering Led Zep IV: “I put the tape on and the first song goes by and sounds bloody awful. Then the second one comes along and that’s really horrid, too... Pagey should’ve fired me at that point"

By the time Led Zeppelin holed themselves up in a dilapidated former Victorian workhouse at the beginning of ’71 to cut their fourth album, they were on the verge of becoming one of the biggest-grossing live acts of all time. 

At the end of the year, gig revenues of $100,000 (£62,000) in the US were commonplace, running hand-in-hand with the notorious drug- and booze-fuelled orgies and excess that seemed to follow the band around wherever the road took them.