This April will be the last chance to see a photographic retrospective that is close to the hearts of many. From the violence in the Congo to that in Biafra, Vietnam, Cambodia and Lebanon as well as crucial moments such as the fall of the Berlin Wall, Don McCullin has confronted the world with raw, shocking images from almost every major conflict of the twentieth century. McCullin, now 77, sits before me. He is not, I am quick to discover, afraid of eye contact.

Perhaps this is one of the most notable aspects to his photography. Eyes constantly stare back at you. We share the penetrative gaze with an emaciated woman desperately trying to feed her starving baby in Biafra or a worn-faced English beggar. “I had a very baby-like face when I began. I think these people used to look at me and think, ‘What’s this kid doing behind a camera in the middle of a war zone?’ So they would look up at me in curiosity.”

“You cannot be objective,” he says. “Sometimes people criticise my work as a journalist because it’s so interrelational, and therefore very self-consciously subjective. What people don’t always understand is that, when you go there, it is with the chance of being killed as well. I gambled my life for the photographs I took on those days.”

The relationship with the subject is, however, troubled. “You press that ‘professional’ button, you think: ‘Is this the best composition, the best expression, the best action shot?’ But then you remember that you are also a human being standing in front of another human being; you’re not just some robot here doing this.”

Amongst McCullin’s work are pictures of starving children, dead bodies, the iconic image of a shell-shocked soldier in Vietnam.“Atrocity pictures can be aligned with pornography, especially if it’s congealed into one big book, you have to be careful. I did take pictures of some really gruesome things; people whose heads that have been blown half away. It can all be very dodgy really in the wrong context.”

Shame becomes a large part of our discussion. The shame of what James Nachtwey calls our “compassion fatigue”, the shame of poking a lens in someone’s face as they are dying, the shame that humanity could do such things. “I’ve had hundreds of starving children staring up at me, thinking I was their salvation. It has not been an easy cross to bare. We’re all guilty. We’re guilty by association. Of course I’m guilty. I feel ashamed standing in front of people with a camera and knowing that I could leave anytime and get myself something to eat. When I was working on some of those AIDs stories, I would never sit and eat in front of them. I would go and hide in a warehouse or somewhere. I know what shame is and that I can be easily part of it. When I photographed the picture of the baby burnt to death, I was full of shame. Not only for myself, but also for the people that did it, the whole thing was despicable; I constantly watch how I behave, checking my moral obligations”.

Referring back to it often throughout his interview, McCullin’s childhood was a time that shaped and formed his attitudes, fuelling the interests that come out in his photography.

“I grew up with the right credentials to know what shame is. I felt ashamed of my background. We lived in two rooms with no lavatory or bathroom; I never starved, but my mother was never there, working as she did, on a railway. I had a huge inferiority complex and yet looking back on it now it was the very best way for me to start, because I knew when I used to go and photograph the poverty stricken places in England, I knew exactly what I was dealing with because I came from it. I had no shame about that.

“My father was chronically ill, my mother was violent and used to get drunk and scream at the neighbours. I was thinking about my mother on the train today and I was thinking ‘why was it that I didn’t love her?’ She did do some amazing things. She was a tough old witch. If someone did something bad in the streets, she’d go out there and brawl with them. My mother battered a man one night. He was drunk, beating his child in the street. She got a huge Dutch ornament and smashed it over this guy’s head; there was blood and chalk everywhere and my mother went off in the police van. She was terrible, in a way.”

McCullin was evacuated to the north of England during the Second World War, to live with a couple that used to beat him and lock him out at night. “We weren’t given a bath for seventeen weeks. There was a scandal in the village one day when someone saw me naked in a flooded field washing myself. They had a chicken farm and just before I left I threw as many chickens as I could into the river. I was bloody angry. All the things that happened to me in the past made me feel in touch with humanity. When I went to war I didn’t just go there as a bloodthirsty photographer wanting to make a living for myself. I went there aware of my humanity.”

His friends were members of a local gang whom he photographed. He sent the pictures to the Observer in 1959, who immediately offered him a job. Since then, he self-admittedly became a ‘one-war-a-year man’, tirelessly travelling to places of deprivation and conflict. He worked for a long time at the Sunday Times Magazine, who he said ‘spoiled’ him, allowing him to cover any conflict he desired. The political events he covered also became personal experiences, which at times would get too much. “I was at a massacre in Beirut. I wasn’t with the Palestinians this time; I was with the people that were murdering them. They brought some women and children down the stairs and the women were looking at the men who were standing with their hands up. We went outside and the man said to me, “if you take any pictures, I will kill you.” I thought, “he will.” I went back into the stairwell where the two men were standing; a bunch of guys came behind and shot the men in front of me, busting their brains all over the wall. I watched it and I couldn’t stop shaking. I told myself, “get a grip, this has only just begun.” They killed everybody, two or three hundred people- just shot down in alleyways: men and women alike. I saw a man shot and his whole head disappeared in one go. There were great rivers of blood.”

I ask him why he would go back, year after year, to places of trauma and destruction. “Because I thought that I could prove I was the man. I thought that if I could take pictures of war in the most dangerous way. I thought I could take pictures of civilians in a way like no-one before me, because I had an enormous amount of compassion. I wanted to bring these photos back and make people do something about all this terrible suffering. I thought I could change things, I was wrong.”

Does he have faith in humanity? “No” is his immediate response. Then he revises his answer, explaining that he did meet very good people; those who came as aid workers, the doctors, the nurses, and civilians. “There is also beauty in war. It’s very difficult to say that but it’s true. There was a mad Swiss doctor when I was in Cambodia, this was at the fall of a city. Men were coming back from the front with their eyes hanging out and their legs missing. Even the carriers of the wounded were being murdered by the Khmer Rouge. You wouldn’t believe the damage that shells can do to human flesh. All the while, this mad doctor would be sitting in his hotel at night playing his cello. I don’t know whether that’s beauty or if he was just bonkers. Tenderness is beauty; bandaging someone’s leg, playing the cello, sharing the little food you have left with another person. I once carried a man from the battlefield on my shoulders who looked like Jesus Christ. At my first battle in Cyprus, I carried an old lady to safety, just scooped her of the ground and ran down the road. I didn’t do it for any glory, I did it because I felt angry.”

In an age without digital cameras, McCullin was unable to check his photographs as he went along. He would take only a very limited amount of film. I wonder whether he was ever surprised by what he had when he developed the camera. “Never. I compose the pictures. Is that bad? I don’t know. I suffer from pre-meditation. I think what’s going to happen now and I’m waiting for that composition to emerge. The images were imprinted on my mind from the moment I took them. I can bring those pictures back to me now without any photograph. They wander into my brain at any moment of the day or night. I am on the verge of insanity.

“The more questions you ask me, the closer to madness I feel. I think I’m a sane person and then I think, “am I?” Sometimes I’ll be in my house and I’ll play Elgar, I turn the music up until the whole house vibrates and the cats are running away. It brings me to tears and I wonder what the meaning of my life has been.

“I constantly review how comfortable I felt being rewarded so many prizes. I wish in a way that I had refused them all; it would have made me a more honourable person, it’s shameful that I accepted them. I was considering burning my negatives, everyone says I’d be mad. This is what the shame has done.”

Don McCullin’s work is currently exhibited at the Imperial War Museum in London. His latest book, Shaped by War, is also available for purchase.