On the trail of the real Lord Byron

They called him 'mad, bad and dangerous to know'. But what is the truth about the life of Britain's most notorious poet, asks Mark Bostridge. And can a major new biography help to separate the facts from the fiction?

In the summer of 1938, a small group including a canon, an archaeologist, a surveyor, and a doctor assembled in an English parish church for a ghoulish, yet grimly fascinating task. Their plan was to investigate the condition of Lord Byron in his coffin in the family vault at Hucknall Torkard.

When the coffin lid was raised, Byron's body – minus his lungs and larynx, which had been briefly enshrined in western Greece – was revealed to be in an excellent state of preservation. It had turned a dark stone colour, but the slightly protruding lip and curly hair, now completely grey, were instantly recognisable from the famous portraits of the poet. There was a drop of blood on the forehead, and Byron's deformed right-foot had been detached from his body at the ankle, and lay at the end of the coffin. In keeping with Byron's reputation as a great and indefatigable lover, his sexual organ was noted as showing "quite abnormal development".

More than a century earlier, Byron's death from fever in April 1824 at the age of 36, while working for the insurgent Greeks in their War of Independence, had been received with shock and disbelief. The young Tennyson inscribed the words "Byron is Dead" into the soft sandstone of a rock near his Lincolnshire home, and later remembered how the whole world seemed to darken at the news. Because of Byron's questionable morality, his body was denied burial in Westminster Abbey, but lay in state in London for two days in an atmosphere of near-hysterical emotion which was only outdone by the funeral procession itself when crowds pushed and shoved to get a sight of the cortege.

Byron had believed himself ostracised from English society because of rumours of his sodomy and of his incestuous relationship with his half-sister Augusta. In 1816, after a bitter separation from his wife, he had left England, never to return, and had spent eight years rolling round Europe in a great black coach in self-imposed exile. Yet the public appetite for everything Byronic – his life, his loves, his poetry – had remained insatiable.

Ever since the publication in 1812 of the first two cantos of Childe Harold, which made him famous overnight, Byron had been public property. Furthermore, the way in which his life seemed to generate his art, the idea that while other writers wrote their lives, Byron lived his writings, only added to his appeal. He was perceived as the first poet to appear directly before the public, expressing his own thoughts, feelings, fears. In the end this contributed to his undoing as the line between art and life became hopelessly blurred: in the words of Walter Scott, Byron "Childe Harolded himself, and outlawed himself, into too great a resemblance with the pictures of his imagination." In life Byron had been starry, but in death he became starrier still as the icon of the Byronic hero – melancholic, beautiful, dissolute – influenced everything from the Brontës to Mills and Boon.

"Byromania" was the name coined by Byron's wife, Annabella, to describe the hullabaloo encircling her husband, and this month sees a fresh outbreak of the phenomenon. At the National Portrait Gallery in London, an exhibition exploring Byron's continuing fascination for a new generation will include portraits of him by George Sanders, Richard Westall, Thomas Phillips, and the marble bust by Bertel Thorwaldsen, while a BBC Omnibus film will attempt to re-evaluate the Byronic myth, with contributions from Byromaniacs like Michael Foot and Lord Gowrie.

The main event, however, is the publication of Fiona MacCarthy's long-awaited biography, Byron: Life and Legend, a beautifully detailed book and one of the great literary biographies of our time. There has always been a frisson of guilt and unhealthy speculation surrounding attempts at Byron biography which dates right back to the burning of the poet's own memoirs in the grate of his publisher John Murray's offices, a month after his death, for fear that they might reveal the truth about his sexual misdemeanours, in particular his bisexuality. In the 1950s, the eminent Byron scholar Leslie Marchand, writing at a time when homosexuality was still a criminal offence in Britain, was expressly forbidden by the head of the Murray firm, which holds the richest archive of Byron material (everything from manuscripts to a lock of Lady Caroline Lamb's pubic hair), from writing explicitly in his pioneering biography about Byron's recurring loves for adolescent boys. MacCarthy is now able to dispel much of the mystery and doubt. She suggests that Byron's often sadistic relationships with women were a reaction to the sexually abusive behaviour that he had suffered from his nurse when he was nine. She also argues plausibly that Byron's true sexual yearnings were for boys, beginning with Edleston, the 15-year-old chorister whom Byron loved (probably chastely) at Cambridge, and ending with Lukas Chalandritsanos, the page whom he pursued (unrequitedly) in his last months in Greece.

Among the great strengths of MacCarthy's book is her examination of the ways in which the life and legend interact, showing how the myth that Byron himself helped to promote masks not only the real man, but also the true worth of his poetry. One of the fascinating aspects of Byron is that his awareness of the value of self-promotion and manipulation of his own image makes him a prime figure in any history of modern celebrity, and has led to inevitable comparisons with the modern rock star. Not that he was perfect material for the romantic hero. He may have become practised at the curled lip, but his striking looks had a pale, effeminate quality, and his right foot was lame at birth. I remember visiting a Byron exhibition at the V&A in the 1970s and seeing two of his surgical boots, used to disguise his withered calf muscle and to make the foot fit an ordinary outer boot. He was acutely conscious of his deformity and went to great lengths to hide it. He also fought a running battle with his weight, and took weight-reducing purgatives. The year before his death he wrote that "I especially dread, in this world, two things, to which I have reason to believe I am equally predisposed – growing fat and growing mad". In this week's Omnibus you can see the scales at Byron's wine merchants, Berry Brothers, which he used to weigh himself. Their records show that at 18 Byron, at a height of 5ft 8in, weighed 13st 12lb, and that six years later he was lighter by almost four stone.

Byron was the consummate showman, whether it was posing in colourful Albanian costume for a portrait, or donning scarlet military uniform to impress the natives of Missolonghi. He kept as strict a control as he could over the visual images of him, instructing Phillips to repaint his nose, and decreeing that he should be portrayed as a man of action with "no pens & books upon ye canvas". Appearance was all, even after his scandalous reputation meant that mothers told their daughters to avert their gaze from him. Literary representations were another matter over which he held no powers of censorship. In 1816 his ex-lover Caroline Lamb published a thinly disguised portrait of him in her novel Glenarvon, and for the next 20 years Byron's appearance in fiction was almost an annual event.

But to what extent has Byron's celebrity overshadowed his poetry and compromised his position in the modern pantheon? In 1999 his work was kicked off the national curriculum and it remains the least known of the writings of the major Romantics. There was always a danger that Byron's name for being "a man first and a poet afterwards" would make his poetry hard to place, and for evidence of posterity's preference for life over literature, one only has to look at the film biographies of Byron in which the poetry is almost entirely incidental to the plotline. Charles Sturridge is currently planning a two-part film of Byron's life for Channel 4, but the pedigree is not encouraging. The earliest biopic was a 1922 silent called The Prince of Lovers (an allusion to Rudolph Valentino, then at the height of his fame as a great screen lover), and since then Dennis Price has limped painfully through the role, along with, among others, a smouldering Richard Chamberlain, a satanic Gabriel Byrne and a best forgotten Hugh Grant.

Although the work is indissolubly bound up with the life, it is still worth reading for all that. Don Juan is one of the great comic masterpieces, a brilliant satire on the hypocrisies of high society with a convention breaking view of female sexuality in which women are revealed as taking the sexual initiative.

"There wasn't much future for a middle-aged Byron", says Fiona MacCarthy in the Omnibus film. Had he lived he might have been proclaimed King of Greece, though it is almost as difficult to believe in Byron in an official role as it is to imagine him bald, rheumatic and toothless. Instead he became the universal template for the glamorously tragic hero and disreputable amorist.

Christopher Hitchens recently remarked that Byron is more like a comet than the meteor to which he is usually compared. While the body lies at rest in the family grave, Byron's perennial fascination will come round again and again.

'Byron: Life and Legend' (John Murray, £25) by Fiona MacCarthy is published on Thursday. 'Lord Byron: Exile on Fame Street', BBC1, Wednesday, 10.35pm. 'Mad, Bad and Dangerous: The Cult of Lord Byron', National Portrait Gallery, London WC2 (020 7306 0055) from 20 November to 16 February