Shakespeare's 'Richard III' set a template for amoral anti-heroes. Mary Russell, like Lady Anne, is seduced every time.

It was the most expensive theatre ticket I've ever bought: €400 to fly to New York to see a production of my favourite play in Manhattan. The story of this obsession begins in the staffroom of an English ghetto school where a teacher of English was making his retirement speech. He was a squat, middle-aged little man with glasses, perfect for mickey-taking by the disaffected products of a run-down council estate - those who could be bothered to turn up to his English literature classes, that is.

He'd been stunned, therefore, to receive a farewell card from the sort of obstreperous teenage girl that teachers dread: loud-voiced, boobs challenging the buttons on her school blouse, given to shouting sexual taunts at passing boys.

Unbelievably, she had written that she would miss him, so that now he stood, in all his balding glory, wondering how someone as uncool as a teacher could have moved a 15-year-old schoolgirl to actually like him.

"I, that am not shaped for sportive tricks/ Nor made to court an amorous looking glass," he told us. "Deformed, unfinished, sent before my time/ Into this breathing world scarce half made up/ And that so lamely and unfashionable that dogs bark at me as I halt by them."

"One of the English teachers," I told my daughter that evening, "made a marvellous farewell speech about a girl in his class. Something about his being a lump of foul deformity and how her eyes had drawn salt tears from his."

"Richard III," said my daughter promptly, "when he woos the Lady Anne over the dead body of her father-in-law that he's just killed. He killed her husband as well." I checked the seduction scene and was hooked.

First, though, to get the facts out of the way. Richard Plantagenet was born in 1452, became king of England in 1483 and ruled for two years until he was killed at the age of 33, calling for a horse at the Battle of Bosworth. During his reign, he endowed the church, supported his extended family generously, ruled well, married his cousin, Anne Neville, with whom he had shared a happy childhood, mourned with her the death of their small son and mourned her own death a year later. In short, Richard III was a passable king whose dull life was partly redeemed by the fact that he died young.

He was killed and succeeded by Henry Bolingbroke - Henry VII, grandfather of Elizabeth. It's here that the fun starts, for Henry was a Tudor and the Tudors had the best spin doctor they could have wished for: William Shakespeare.

His dramatist's pen reinvented Richard as the archetypal enemy: malevolent, murderously scheming, misshapen of body, hated by his own mother and reviled by everyone.

"Even so," a friend remarked after she'd seen a performance of the play. "I wouldn't mind his slippers under my bed." And I couldn't but agree, for Shakespeare's Richard, though wicked in the extreme, is dangerously attractive.

"Since I cannot prove a lover to entertain these fair well-spoken days, I am determined to prove a villain," he says.

And he does, all the way through the play, in fully-fledged bad-boy mode. Accepting that he is deformed and unlovable but knowing exactly how to turn these things to his advantage, he speaks the unspeakable, flaunts his deformity, dares us to feel sorry for him and, when we do, laughs in our face, unfettered by the constraints of acceptable behaviour.

With Queen Elizabeth I paying the piper - the theatre flourished in Tudor England - Shakespeare embellished his Plantagenet anti-hero, drawing on reports that were clearly biased. History is written by the winners, and Shakespeare's main source was John Morton, who was Henry VII's archbishop of Canterbury. Regarding Richard as the arch-enemy, Morton spread the rumour that he had lingered two years in his mother's womb and had been born with a full set of teeth. In no time at all, the rumour was taken up by none less than the sainted Thomas More. The rest is history.

In fact, though the real Richard had been born with nothing worse than one shoulder slightly higher than the other, Shakespeare depicted him as having a hump, a withered arm, a dragging limp.

Laurence Olivier had him decked out in a black, fringed wig while Anthony Sher had him on crutches.

He is the only Shakespearean character who gets to open a play with a soliloquy all about himself, so he dominates the drama from the start - one reason why actors love to play him.

Once I was in his thrall, there was no stopping me. I joined the Richard III Society and went with other members to walk the battlefield at Bosworth. Each year I check the Guardian's obituaries page and there is the entry: "Plantagenet, Richard. Remember before God, Richard III, King of England . . . who fell at Bosworth Field, having kept the faith . . . August 22, 1485."

I've even got a T-shirt that reads: "And thus I clothe my naked villainy." Over the past few years, I've seen every performance it's been possible to get to. One in Copenhagen had Richard enveloped in frills and flounces. In Tbilisi, the Georgians made him into someone else altogether. Ian McKellen, on both stage and celluloid, played him as a 1930s, trench-coated fascist who drove his wife to overdose. Derek Jacobi ground the floor of the stage in impotent rage at having to be a soldier in time of peace.

During its Season of Regime Change last year, the Globe in London put on an all-female production with the marvellous Kathryn Hunter playing Richard, devious and agile as a spider sidling up to his victims to ensnare them. Barry Rutter, actor/manager of Northern Broadsides, sat on his throne wrapped in an enormous crimson cloak that covered the stage like a sea of blood.

There was Simon Russell Beale at Stratford, thick-necked and thuggish, the spotlight switching from him to the upstart Welshman, Henry Bolingbroke, as he starts his duplicitous speech about how great England will be under the Tudors: "Enrich the time to come with smooth-faced peace,/ With smiling plenty and fair prosperous days!" How Gloriana must have nodded her pleasure at Shakespeare's choice of words. In this Stratford production, the director had Richard give a slow hand-clap from the shadows to which history has relegated him, for he knew - as we were yet to learn - that the reign of the Tudors would be characterised by plunder, piracy and penal days.

Last year, at Stratford again, as a special treat, they put Richard on a couch and had him questioned first by an analyst and then by us groupies. "Why are you so horrible to your mother," I asked. His reply? "Because no matter how hard I try to emulate my father and my older soldier brothers, I never measure up to her expectations." He was right. "Thou toad," she spits at him, "Thou camest on earth to make the earth my hell . . . "

And what about the distraught Lady Anne? She who, having wooed and won, he discards? "I'll have her but I will not keep her long," he shrugs, in one of his many asides to the audience, implicating us in his villainy as he does throughout the play. Even writing the words, I groan. How could she have been taken in by the sweet-talk of this treacherous man? "Don't take the ring," I want to shout at her. But she does, every time.

Shakespeare, of course, was writing for a different age. By making his main character a hunchback (nowhere in the play is he called a humpback), he uses Richard's outer deformities as a theatrical metaphor for his inner evil. Which is why the production in Manhattan's Public Theatre fed my obsession, for there I was twice challenged - first by the American accents and secondly by the fact that Richard was four feet five inches tall and played by a dwarf, Peter Dinklage, star of the film, The Station Agent.

The accents proved not to be a problem, for this was a traditional production with the actors faithful to Shakespeare's speech patterns. Dinklage, on the other hand, brought something extra to the play, as all intelligent actors do. His voice thundered out of his foreshortened body, his eyes darkened, then flashed with lightning. Once again, the Lady Anne was seduced.

"Was ever woman in such humour won," he asked us contemptuously. Yet again I groaned. Later, as the younger prince play-acted with him, there was a terrible, sudden silence when the boy said: "Uncle, my brother mocks both you and me because I am little, like an ape." And we, the audience, held our collective breath.

But don't get me started on those little princes in the Tower. Though his enemies accused Richard of having arranged their murder, there has never been any proof that he was, in fact, guilty. But then, I'm biased, seduced.