McCullin's early years have a familiar cinematic ring to them. His childhood and adolescence in the East End of London evokes images we've all seen a hundred times on screen of harsh urban poverty, adolescent street gangs, scrapes with the police and the harrowing death of a beloved father. The backdrop is World War II and the blitz, a dramatic scene from which might provide the film director with an inviting opportunity to fade forward to a shot of our now mature, ruggedly handsome hero at work in the killing fields of Vietnam.
One of the century's most celebrated war photographers, McCullin made his name in Vietnam and then proceeded to see action in the Belgian Congo, Beirut, Biafra, Amin's Uganda, Ulster, El Salvador, Iraq. You name it. To pick out one movie narrative from the many available would be a struggle but perhaps the amphibian assault mission across the Perfumed River with a battalion of American marines, 70 of whom he saw die over the next 12 days at the hands of the Viet Cong, would make for some powerful box-office fodder; as might the sheer terror of the days he spent in the custody of crazed Ugandan soldiers who were obliging fellow prisoners in adjoining cells to hammer each other - literally - to death.
Francis Ford Coppola could have a riot with this stuff but he would be at a complete loss as to what to make of the last 15 years of McCullin's life, complex material more suitable for a slow-moving Mike Leigh melodrama. For 1982 was the year McCullin decided to stop living dangerously. Two things happened in quick succession that changed him utterly. A woman in Beirut gave him the beating of his life and his wife, Christine, died of a brain tumour.
He abandoned war photography, quit the Sunday Times - his journalistic home for the previous 18 years - and retreated to a house in Somerset to take pictures of cows, trees, bogs and stormy skies. That's where his autobiography, Unreasonable Behaviour, completed 10 years later, abruptly ends. He had one last fling with war in 1991 when he went on assignment for the Independent to chronicle the horrors Saddam Hussein unleashed on the Iraqi Kurds, but he discovered he had lost his appetite for horror. As he wrote in his recently published photographic autobiography, Sleeping with Ghosts - images that stun with a force his written memories cannot convey - the sight of all the burnt and injured Kurdish children reminded him why he had retired from war in the first place. "In some respects I wish I hadn't gone. The immorality of the situation seemed intolerable. Did I need to face all this yet again?"
He suggested we should meet for our interview at the Gramercy Park, a faintly seedy New York hotel where visiting British journalists often stay. "God knows why," he said over the phone, "though, maybe we like that whiff of Graham Greene. It's just like the sort of place I've stayed in a hundred times in South East Asia." He spoke with gentle self-mockery, poking fun at ancient warhorses - he's 62 - for whom old habits die hard. Not at all what I had programmed myself to expect after the gut-wrencher of reading his two books, never mind the legend-drenched prose he has elicited from John Le Carre. "It's life, and it's love outraged, it's a cry of fury from deep inside McCullin's feeling heart," Le Carre wrote of one of his photographs. "He can do nothing lazily, nothing that does not touch upon the enigma of existence."
I discovered, when the enigma became flesh in the Gramercy bar, that, sure, you can choose to see McCullin in this intense heroic light - as Rambo meets Dostoyevsky - if you wish. He did spend a fair part of the two hours we sat together twisting himself in knots about guilt, pain, fear, the meaning of life and death. But he's also kind and considerate to a fault, apologising for things over which he has no responsibility - like the fact that I had missed lunch, or that I'd had to catch a 45- minute flight from Washington to New York - in that excruciatingly accommodating, delightfully bonkers English way. And, in another reassuringly normal reflex, he's one of those blokes who can't resist the urge to have a go at "the bloody Americans". "All this `Have a nice day!' All this `Enjoy!' I can't bear it. You feel that urge, don't you, when they say `Enjoy'?" he said, looking around the room, lowering his voice to a comic whisper, "I mean, that terrible desire to reply, `Fuck off!'"
In the here and now, I discovered, McCullin is relaxed, polite, even cheerful but touch on his past, that part of him on which his reputation rests, and he snaps into a sort of lugubrious trance. Try asking him, for example, what satisfaction he's derived from his photographs. "There was never any satisfaction." None? "Only the satisfaction in that lesser degree of knowing that when people opened the Sunday Times colour magazine they would see the unfortunate circumstances of other people as opposed to the cosy, successful circumstances of their own lives. But you couldn't be satisfied being in a jungle clearing and seeing two prisoners that had been captured and suddenly hearing someone say, `OK, kill 'em'." But what about the satisfaction of knowing he'd taken a great picture? "Sure. There was that burst of adrenaline, but then you asked yourself `what does the picture mean?' Naively, I used to think I could change the world. But, of course, I didn't change one iota."
This futility he claimed to attribute to his life's work was partly, it seemed, an expression of a self-effacing, self-deprecating personality - yet another typically British character trait that his foreign adventures had failed to erase. He might be the living legend that every young photo- journalist everywhere dreams of emulating, but, when he talked about the danger he once courted for a living, he insisted on looking back more with scorn than admiration. "I used to chase wars like a drunk chasing a can of lager. I couldn't pass up the wine shop. Now, basically, I'm a cured alcoholic. A cured war junkie."
But there was something about this cynicism that did not quite ring true. Either he felt a need to keep up this self-disparaging pose ("I hate drawing attention to myself," he said), or he is a man of shifting moods who does not fully know his own mind. Or both. Because, reluctant as he may be at one level to acknowledge any lasting value in what he has done, get him to talk about the detail of how he takes his pictures, persuade him to nail down what really drives him, and he starts speaking solemnly, with a candid sense of purpose.
"When I was in the presence of grieving sons or daughters or parents I always tried to exercise the utmost dignity, to respect their sorrow above my work. I was always looking at their eyes for approval before I took a photograph. I always moved very slowly with my camera - as if I moved it might explode - just waiting for the right moment."
If you look closely at his face you'll understand that this delicacy of sensibility he projects is sincere. He looks craggy and young, pugnacious and melancholic at the same time. People have said he looks like Steve McQueen. Not really. Maybe Steve McQueen's harder, more complicated older brother. His nose has been broken, but so, too, has his heart.
It was his asthmatic father's death, when he was just 14, that did him in. A big man, he had wasted away and went to his grave weighing six stone. "My dad's death cast a gloom over me that I've never shaken off. It's fashioned my whole life. Even to this day, I can feel personally upset about my father's death. Even to this day, I'm very pissed off about it. It's still there, like the smell of coffee and toast in the morning. Everything I've done since has been to try and honour that man's name."
He has relived the scene at his father's deathbed over and over, capturing each moment - a Vietnamese woman draped over the chest of her dead husband, a Kurdish woman holding the hand of a dying boy - always in black and white, always in photographs he printed deliberately dark, in lighting that was invariably gloomy. Even the Somerset landscapes from his post- war era are gloomy, their atmosphere defined by black louring clouds. In his autobiography, he blames his father's death on "the million coal fires" that "belched dark smoke" into the winter air. In Vietnam, he told me, he preferred taking pictures in gloomy weather. "Those were the days I preferred. I didn't like sunshine. I thought it gave the wrong sense of mood."
One day he got the mood terribly wrong and the memory is seared in his mind as vividly as his father's death. A woman in Beirut who had just discovered that her entire family lay dead under a building flattened by a shell was shrieking with pain. He pointed his camera at her and clicked. She ran towards him in a rage, "completely ape-shit". "I just responded very quickly and I made a colossal mistake I'd never made before. I had always prided myself on avoiding such an incident. I had always considered myself the master of decorum. But this time I blew it and she punched the life out of me, and I had to take it. The last thing I wanted to do my whole life was to heap more pain on people. But that day in Beirut I felt the biggest Judas in the world as I walked away."
And, save for that brief sortie in Iraq 10 years later, he never returned. He paid his penance back home a few months later when his wife, from whom he had separated but to whom he still felt deeply attached, died on the very morning that their son was due to get married. Bizarrely, bride and groom decided to go ahead with the ceremony. "And I took the wedding pictures and - I'm not joking - those were the most difficult pictures I've taken in my life. I had to go through this farce. Everybody was standing there trying to smile but really they all wanted to cry."
It was almost as if all the suffering people he had ever photographed had conspired that very day to exact hideous revenge. Little wonder that he ran off to the moors to dwell in limbo solitude for a decade. Little wonder - though he resented it bitterly at the time - that a journalist who met him at the end of that period called him "a misery".
But today that would not be an appropriate description of the man. A smile does not look entirely appropriate on that face yet one does surface with surprising regularity. He has a new project, a book on India whose photographs are soulful but not always sad. And he has what he calls "a new adventure", a wife whom he married, aged 60, in October 1985 in a ceremony of redemption at his Somerset home. "It was a beautiful Indian summer's day. We had a marquee in the garden, flowers, champagne, a 1930's Rolls-Royce to take us away. It was a classic day. Classic. Isn't it funny to go through all those 30 years of misery and pain, and suddenly, one October day, you're sitting in this beautiful village marrying a beautiful blonde American woman who you adore?"
Her name is Marilyn Bridges and she is a distinguished photographer in her own right, a qualified pilot famous in America for her aerial landscape work. She joined us in the Gramercy towards the end of the interview and, on seeing her, his eyes did actually light up, the weight on his brow did visibly lift. She said she had to go off and buy some stuff and she'd join him later but he said no, he wanted to walk the streets of Manhattan with her.
The time had come to say goodbye. We'd been talking for two hours, going this way and that on his guilt, his dead, his existential confusion, his satisfaction and lack of it in what he had achieved. But now the clouds had gone and everything seemed clearer. "I think I've had an amazing life, actually," he said, glancing fondly at his approving wife. "The gods have been kind. I have precious years left and a pretty woman who's given me new horizons to look at. Things aren't so bad, are they? I still have energy and lots still to do"
`Don McCullin: Sleeping With Ghosts' is showing at the Barbican from 11 September to 14 December
`I was haunted by images of death and destruction, but the shocking nightmares I used to have come less often now. I wanted peace, but I knew the feeling wouldn't last.' Bradford, 1978. Weary of war, McCullin took himself off on a tour of Britain. He walked the streets of Bradford, and eventually photographed this family at bedtime (main picture); Afghanistan, 1979 (above left).Within months, he was back on the front-line, among the Mujahedin
World at war (clockwise from top left): East Beirut, 1975. Palestinians are driven from the Quarantina enclave; Hue, 1968. A dead North Vietnamese soldier lies with his personal effects scattered by plundering soldiers; Hue, 1986. `It was somewhat religious-looking, like an effigy,' says McCullin of this image of a US marine shot by sniper fire. He later helped carry the wounded marine to safety; Limassol, 1964. A Turkish gunman in the Cyprus civil war; Londonderry, 1970. The Anglia Regiment counter-attacks a group of stone-throwers
This England: Bradford, 1978. Stripper in a pub (above); Finsbury Park, 1958. `Guv'nors of the Seven Sisters Road' (left) - this Observer image of a street gang in a bombed and vandalised building was McCullin's first published picture
`In my present home in Somerset, I try to eradicate the past... now I create my own days in my garden shed (from top):Still life with Dahlias and Lilies, 1995; Still Life with Wine Jug and Mushrooms, 1996; Roman Hill Fort, 1986 - the view from McCullin's bedroom window