A giant, mechanical lotus flower creaked open on the Earls Court stage, "Honky Tonk Women" clanking from within it, and a rakish figure leapt out in a ruched satin jacket, crimson strides and a floor-length silk scarf that swung above our heads in the second row. I'd never seen Mick Jagger in the flesh and I felt breathless, almost winded.
The word "cool" would have undersold him in 1976. He cruised at a level of unimaginable gorgeousness, a head-swimming symbol of all that was dissolute and desirable. He seemed to have stepped directly from the fleshpots of Babylon, louche and foppish but hell-bent on revelry. He looked snake-like, acquisitive, rapacious, insatiable. Every inch of him roared rebellion - the glitter, the pale-blue eyeliner, the pouting lips, the arrogant strut that dissolved occasionally into a cartoonish, multi-limbed blur of pretend panic.
The clothes he wore back then were calculated to traumatise anyone over the age of 40, a voguish glam-rock androgyny shot through with powerful echoes of the past, the silk shirts and frock-coats summoning the bohemian flair of Baudelaire — the man who declared "all pleasure lies in evil" — and the fey, smouldering charisma of the kind of Romantic poet who spent his downtime divinely composed upon a chaise-longue swigging a phial of laudanum.
In fact, when Jagger read extracts from Shelley's Adonaïs at the Hyde Park wake for his band's founder-member Brian Jones seven years earlier, he was wearing what could best be described as a blouse: so far ahead of the male curve he was threatening.
The way he dressed captured a moment in time, a game-changing era when the upwardly-mobile lower-middle-class rock stars met the rich-but-slumming-it daughters of the aristocracy and squired them around town, forming a new brand of cross-class alliance. For the girls, a high-profile scrubbed-up bit of rough; for the boys, a moneyed and press-magnetising bit of posh.
Everything Jagger wore back then had elements of the elite world he was entering — the floral shirts, the gemstones, the blazers, the Panama hats, the cream suits and watch-chains, the extravagant rings.
When he hooked up with Marianne Faithfull — in the blinding way of any golden couple — they became twice the sum of their parts, an effect even further enhanced when he married the girl the press routinely dubbed "the Nicaraguan firecracker". In one unforgettable wedding picture taken in the back of their Roller, Bianca seemed barely clad and Mick frozen in closed-eyed ecstasy with a champagne bottle clamped between his thighs.
Of course, the incandescence he's sustained for five long decades is now expressed differently. He still favours the top end but with the edges artfully distressed (a Hemingway suit with a T-shirt and trainers). Which is fitting as that sense of cool has modified, too, the apparent abandon of his reckless past exchanged for fierce control and the relentless scrutiny of his professional life.
Happily so: if he'd stayed the same, The Rolling Stones would now be playing clubs instead of stadia and we'd have someone else's picture on the cover of Esquire.
Taken from the Esquire style icons issue, out now.