The gilded road to a pauper's burial

The curtain rises on the British Library's six-act tribute to Oscar Wilde to reveal a shrine-like case. Inside are three objects: a silver mug resembling a chalice inscribed with Wilde's initials; an envelope decorated by him and containing a lock of his dead sister's hair; and a photograph of the infant Oscar, aged two, in a blue velvet dress. The caption tells us Irish children were often dressed as girls, as the faeries were prone to steal boys. As if that weren't metaphor enough, these three relics seem prescient of Wilde's life to come: as though his very genesis were wreathed in a pseudo-religious, martyr-like symbolism; as though, even before he'd done anything, Wilde had assumed a mythic status, a faerie child already stolen by the gods.

The curtain rises on the British Library's six-act tribute to Oscar Wilde to reveal a shrine-like case. Inside are three objects: a silver mug resembling a chalice inscribed with Wilde's initials; an envelope decorated by him and containing a lock of his dead sister's hair; and a photograph of the infant Oscar, aged two, in a blue velvet dress. The caption tells us Irish children were often dressed as girls, as the faeries were prone to steal boys. As if that weren't metaphor enough, these three relics seem prescient of Wilde's life to come: as though his very genesis were wreathed in a pseudo-religious, martyr-like symbolism; as though, even before he'd done anything, Wilde had assumed a mythic status, a faerie child already stolen by the gods.

It was the way Wilde saw himself. In another display case is a "Confessional Album", pre-printed like a Smash Hits questionnaire, which gave Oscar the opportunity to itemise his aesthetic circa 1877. Favourite colour? " Coleur de rose". Tree? "Stone pine or Lemon Tree". Object in Nature? "The sea (when there are no bathing machines)". Book to take up for an hour? "I never take books up for an hour". The archness is all. Aged 24, Oscar was already the sum of his parts, posing in loud checks and tight little bowler as the product of his spiritual mentors - a dour John Ruskin in socialist tweed; Walter Pater lascivious in an extravagant moustache. But it is America that makes him into a superstar, a fey multiple replicated in the photographs shown here and cartoons as he tours from sea to shining sea, used in advertising in the same way 20th-century advertising would use Magritte or Warhol. You half expect the slogan, "What becomes a Legend most?"

Back in Europe, eschewing the velvet breeches of his US tour ("Strange that a pair of silk stockings should so upset a nation!"), he announces "the Oscar of the first period is dead" with a Neronian fringe. Oscar is now a family man, married to Constance, a she-Wilde, with his sons as little Oscars, all kitted out in aesthetic dress. But he is also the literary celebrity, the fur collars ever more deluxe, the handwriting ever more florid in letters scented with narcissus and vice, sent to a series of doe-eyed and bookish boys, adoring poets and teenage fans. The exquisite product of a century of industrialisation and dissenting romanticism, Wilde relied on the modern world to take him to the provinces, to give clerks from Croydon a frisson of decadent sophistication without ever having to take the tram to the Café Royal. In other photographs shown here sub-Wildean acolytes like Max Beerbohm and Will Rothenstein pose like 19th-century Pet Shop Boys, devotees to the cult. It is a world of Dorian Gray's decaying beauty, and Salomé's perfervid guilt. A world running headlong into disaster in which Wilde became the sacrificial lamb in astrakhan, with Lord Alfred Douglas as his Salomé - poisonously beautiful, all floppy in his linen suit and bow tie, promising unlimited "renters" and feasts with East-End panthers, but not love.

The dramatic apotheosis of this show and Wilde's life comes as it all falls in to the black hole of the Old Bailey, a truly theatrical undoing. On the eve of the trial, Toulouse-Lautrec (in a newly rediscovered portrait) depicts Wilde as a cherub-lipped Buddha replete in his own depravity, more Neronian than that fringe could ever be. It looks down on the doomy documents themselves displayed here: the court transcripts, and the Marquess of Queensberry's illiterate (and illegible) "posing as a somdomite" card, heavily marked by some clumsy clerk of the court as exhibit "A", still seething with mad anger after all these years. You can even stand on the tiles from the floor of Wilde's cell at Reading jail, and read the now crabbed handwriting - as if confined by its walls - on pathetic petitions to the Home Secretary, another pre-printed questionnaire to be filled in by a Wilde reduced to numbers: "C.3.3." Offence? "Gross Indecency". Confession? "Sexual madness". And here, in one dim-lit case, the most explosive document of all, written on venal blue paper - the text of De Profundis, bitter with love and venom: it would never fit in the red morocco box in the case behind it, gilded with the words "Bosie from OW."

At the last Wilde regained his initials, but they were not his own. The final artefact in this exhibition is an evening shirt embroidered "SM" in blue for Sebastian Melmoth, the lastmask, a character out of Wilde's own books exiled to a dingy Parisian hotel. The cuff-links are tawdry and gilt; the buttons ill-matched; but it is a martyr's shirt, for all that, worn to keep off the chill as Oscar went, not to his execution, but to his grubby death bed and thence to his "sixth class" pauper's burial. Processing through this extraordinary, intimate exhibition, you are reminded that underneath that glittering, self-promoting carapace, as bejewelled as the Comte des Esseintes's tortoise, was a real human being. And when you do remember, it is enough to make you weep.

'Oscar Wilde: A Life in Six Acts', The British Library, NW1 (020 7412 7332), to 4 February, 2001