Orson Welles would have been 100 this month. When he died in 1985, aged 70, the wonder was that he had lasted so long. His bulk was so immense, his productivity so prodigious in so many areas, his temperament so exorbitant, that he seemed to have been part of the landscape for ever. Never was ruined greatness so visible. The other great auteurs maudits of this century, Abel Gance and D.W. Griffith, disappeared into silence and oblivion. Eisenstein simply died young. Not Welles. Every time he trundled insincerely through some commercial for cheap liquor (he, the great bon viveur; he, for whom the very word commercial was an insult when applied to film), he sent a pang through the world’s heart.

Pity, for the man who made Citizen Kane, three other masterpieces including the peerless Chimes at Midnight, and at least two lesser but exquisite short films? Pity, for the man who revolutionised radio, whose theatre productions have never been rivalled for audacity and innovation, whose acting performances in the few good films he made for other directors (The Third Man, Compulsion) will never be forgotten? Yes, pity for what might have been: the very thing that haunted Welles himself. ‘Considering what I thought of myself at 14, I’m a mess,’ he admitted. ‘I started at the top,’ he famously said, ‘and worked my way downwards.’ Where did it all go wrong? is the unspoken question behind every utterance he ever made about himself, and was the all-too-clearly articulated question posed by the obituaries, more than one of which were headed with the phrase ‘Whatever Happened to Orson Welles’?

Time has an astonishing capacity for swiftly shifting perspectives, however, especially in the case of those artists who seem to exist in a perpetual blaze of self-advertisement. The more Welles appeared on television chat shows, as he so frequently did in the last ten years of his life, telling his tale, Ancient Mariner-like, the less possible it was to see beyond the myths — the media’s myth of an excessive and indulgent spendthrift, recklessly abandoning projects because he feared completing them, and his own, of a constantly outwitted innocent, a simple artist foxed by wicked producers and studio heads. The problem was compounded by Welles’s imaginative attitude to facts: as any great storyteller would (and Welles was one of the supreme raconteurs of the 20th century) he was always reshaping his history into a more colourful, more entertaining narrative, deftly adapting his approach to his listeners.

Talking to the eggheads of Cahiers du Cinéma, he insisted that everything he did was premeditated, based on strong theoretical positions; speaking to Michael Parkinson, on the other hand, he claimed that he made it all up as he went along. He made The Lady from Shanghai, he told Peter Bogdanovich, after seeing someone reading the novel and thinking that it was a great title for a film; he never actually read the book, he said. But the original book was called If I Die Before I Wake, it had been optioned by the studio, and it was already in full development when it came to Welles. Of course, Welles’s version is a much better story. As to his personal history, his father was, according to Welles, now a Bohemian American aristocrat, now the owner of factories, now the inventor of the automobile; he was in fact the chief clerk of Badger Brass, a small but successful Wisconsin firm in which he had shares that he sold to great advantage, and what he invented was a brass lamp for the outside of cars. On other occasions, to other listeners, Welles confided his conviction that his father was in fact the great Russian bass Fyodor Chaliapin, or possibly Edward VII. Rather less charmingly, he claimed to have heavily influenced the screenplay of The Third Man and to have guided its director Carol Reed in the making of it. In fact, Welles worked on the film for a total of six days, contributing his irresistible charm and a couple of wonderful speeches, including the deathless lines about the Swiss and their cuckoo clock and leaving an indelible impression: but the film is, in every frame and at every level, Reed’s.

Since he died, it has proved possible to unravel this skein of fantasy and caprice, and, as is so often the case with fabulists, a much more interesting reality has been revealed. Welles always had his passionate followers, notably Bogdanovich, but they were a little too inclined to buy into the central narrative of a wronged giant. Then, alarmingly, he fell into the hands of the structuralists and the semioticians, who feasted off him to their immense satisfaction and to the bewilderment of the world at large. The quest for meaning in Welles’s life and work eclipsed the human reality; it was still impossible to see the man as he lived and breathed, to acknowledge his contradictions, which, like everything else about him, were on a gigantic scale. But increasingly, the man and therefore the artist is beginning to emerge. Detailed examination of his life, day to day, is producing a figure who at last resembles a member of the human race. Not that there was anything ordinary about Welles: he was not as others. ‘A superb bravura director, a fair bravura actor, and a limited bravura writer; but an incomparable bravura personality,’ was the judgment of his fascinated but critical admirer Kenneth Tynan. Though it contains a truth, it is a shallow judgment. Welles was a giant: gigantic in his physical being, in his appetites, in his abilities and in his imagination. He often behaved like an ogre, but there were great reserves of gentleness within him which he could sometimes reveal. His capacity for having fun — a commodity not much in evidence on most movie sets, where life is earnest, life is real and time is money — was immense.

But his energies, despite being increasingly challenged by his sheer avoirdupois and its attendant ailments, were titanic. Writing his life as I have been for the past 25 years, I have been constantly bewildered by the amount he packed into every day. A week in his life is worth a year in another man’s. Besides the films (which sometimes stretched over years in the making), there were plays directed, and sometimes written, by him, in which he also played the leading part — a modern version of Dr Faustus in Paris starring Eartha Kitt, Othello and Chimes at Midnight on stage in London and Dublin, respectively, a two-hour physical theatre condensation of Moby-Dick in the West End with him, inevitably, as Ahab. Welles believed this last show to have been the best thing he ever did in any medium; it ran to poor houses for three weeks in a modestly sized theatre, but Peter Hall said it was one of the most perfect pieces of theatre he had ever seen. He made a short ballet, The Lady in the Ice, in London for Roland Petit, not much liked, but he did it, on a colossal scale, in the massive old Stoll Theatre off Kingsway. After the disaster of his King Lear in New York, he immediately went to Las Vegas to do his hugely ambitious Magic Show for a week to packed houses, suspending his lovely assistant in the air and predicting the outcome of The $64,000 Question. After appearing on I Love Lucy, he made a half-hour television film for Lucille Ball’s company Desilu, The Fountain of Youth, which was one of the wittiest, most original television programmes of the 1950s; its freshness and legerdemain are still hugely entertaining. He even won a prize for it; but the series of which it was the pilot never got made. This was not a conspiracy against excellence, or against Welles; elsewhere in American television, producers were lining up to offer him vast sums for ambitious productions, but he refused: he would have had to cede too much control to the executives.

In the end, that’s what it always came down to: Welles insisted on ultimate authority. He refused to be pushed into the formulaic: for him, every work of art was — had to be — an experiment whose outcome was unknown. Paradoxically, the more experimental the work, the better the resources he needed. He spent a great deal of his life as a film-maker working with inferior technicians and second-rate equipment; his long exile in Europe, where he made Othello, Mr Akadin and The Trial, gave him more freedom but less quality, and it shows, on both counts. Had he found some kind of modus operandi with a producer, he might have achieved a great deal more, but he could not tolerate any form of constraint. His extraordinary life is filled with paths not taken — television is a notable example. He arrived on the scene when television was in its infancy: he could have seized it as he had seized radio in the 1930s and raised its game spectacularly. But he would not accept being trammelled in any way. The only way he might have achieved his full potential would have been if he had acquired a studio of his own, as Chaplin did, as Preston Sturges did. But that kind of nous was fatally lacking in Welles’s temperament. He did it his way: and the result is a body of work that is never less than fascinating, though often less than perfect. What it all has, though, masterpieces and mishaps alike, is an unbridled joy in film-making and its possibilities: the films embody the carnal pleasure Welles had in their making. Which is why Citizen Kane remains the film that has inspired more young men and women to become film-makers than any other film ever made, and why contact with Welles, in his 100th year, is as intoxicating as it ever was.