Half a century or so ago, in a world bearing only an incidental resemblance to the one we currently inhabit, the record collection of any aficionado of ‘progressive rock’ would inevitably include album sleeves with designs credited to Hipgnosis. The Hipgnosis signature technique involved elaborately staged or – though it wasn’t immediately apparent – cunningly manipulated photography: photoshopping before Photoshop. The hallucinatory visions that graced the sleeves of such albums as Pink Floyd’s Wish You Were Here (which shows two besuited men shaking hands on a sunlit plaza, one of them a stuntman on fire) and Led Zeppelin’s Houses of the Holy (featuring naked blond children climbing up huge columns of rock; only two children were photographed, and the images were replicated in the darkroom) were created the hard way: someone had to stage the setting and take the photographs. In those pre-digital days, ‘picture research’ didn’t mean a Google search, but a skim through piles of old books and magazines.

In the case of Hipgnosis, that someone was co-founder Aubrey Powell, the more practical, personable and business-minded half of the founding partnership, who worked alongside Storm Thorgerson, the cantankerous visionary and conceptualiser who derived ideas from dream imagery and esoteric visual puns. When Thorgerson had a dream in which