“I operate not as a photographer but as a human being.” This statement by Don McCullin is an obvious but important reminder when viewing his visceral pictures of some of the most awful wars and famines of recent history. The camera is unfeeling. But McCullin makes pictures that register emotions and feelings and it is here his skill as a photographer, his artistry, is central.

Tate Liverpool’s well-conceived retrospective gives us an opportunity to reconsider the extraordinary life’s work of Don McCullin and while he says he is not an artist, the aesthetic nevertheless plays an integral part in his photography. He does more than document events. His pictures are knowing, expressive and felt.

McCullin is a skilled printer and all the black and white photographs of this retrospective were printed by him. The dark tonality of the printing is part of their expressive force. “Darkness, to me, is energy. When I energize my prints in the darkroom, I inject more and more darkness into them,” he says. “But I don’t consider it to be darkness. I consider it to be strength.” That his pictures might now be seen in museums does not diminish their power. Indeed, such contexts allow us the time and space to reflect upon what his pictures mean at a time when photojournalism is too often subsumed to spectacle and compromised by consumerism.

It was through the pictures of a gang of lads he had grown up with in Finsbury Park, ‘The Guv’nors’, that he made his mark in the late 1950s with a publication in The Observer. The newspaper’s interest was sparked by the killing of a policeman as a result of a fight among rival gangs and the beginning, as McCullin notes, of the way in which his life has been linked to tragedy and death.

From the outset his interest and affinity has been with the way in which ordinary people are caught up in historical events. His first, self-initiated, assignment in Berlin in 1961 registers this time of tension and political uncertainty through acts of witnessing and watching, played out between people segregated by the wall that went up between them, as well as the troops amassed on either side. It was the beginnings of his preoccupation with the power of the portrait and the dynamics of the look in photography.

The civil war in Cyprus was his first conflict and encounter with the dead in warfare. The power of his pictures showing the bodies of Turkish Cypriot men killed in their home was dependent upon him also showing their family’s vivid expressions of grief. It was in relation to this experience that he has spoken about the beginnings of “self-knowledge”, stepping away from feelings of resentment over his life being uniquely tough and “learning empathy”.

These pictures register death through its impact on families. Through the faces of the bereaved. But he also shows us the chilling processing of the dead through the detail of the soles of the boots of corpses in the back of a British Army Land Rover. As the presence of the Land Rover signals, the violence witnessed is not without British involvement. It was in British and United States interests to continue the unrest after independence in 1960.

For his pictures made on assignment in the Congo, he gained access to places forbidden to photojournalists by pretending to be a mercenary—a deception that nearly cost him his life. Mercenary with Congolese Family, Paulus, Northern Congo, 1965, scuppers any normalcy associated with the convention of the formal posed group portrait by deploying it in a colonial situation fraught with tension and fear. The figure of the armed mercenary in the picture reflects his own dangerous entanglement with such people in a conflict where, as he has said, “evil men prevailed”.

In Cyprus, McCullin had stopped photographing to carry an elderly lady to safety and he did the same with a marine in Vietnam. In a brutal series from the Congo, depicting captors tormenting young rebel fighters before killing them, one of the boys appears to be looking straight at McCullin. The appeal of eye-to-eye looking is something that is often used in the photography of war. But the horror and tragedy of the look in this picture is that McCullin is helpless and cannot alter the young rebel’s fate.

In his powerful head-on portrait of the shell-shocked American soldier in Vietnam, the young man’s terror and fear are forcibly registered through the deadness of the thousand-yard stare and the fixity of his stance. Stripped of expression, his blankness becomes just as strong an index of pain and suffering as the expressivity and animation of the grieving that McCullin is also so adept at capturing.

In the making of the photograph of a fallen young North Vietnamese soldier, he has spoken of how it was the only time he altered what was photographed. McCullin was appalled at having witnessed how the dead body had been ill-treated by two American soldiers; hunting for souvenirs they had trampled on his possessions, including photos of his mother and sister. Arranging such personal effects into a still life beside the body, McCullin honours the death of this young man and finds an effective means of countering the abjection and anonymity so often associated with photographs of the dead in war.

Much as he hated the looting soldiers, he was as he said, “part of them. I was sharing their food, their uniform, their daily lives.” But their enemy was not his enemy. While he pictured stricken and injured American marines, he also showed them tormenting a blindfolded old Vietnamese civilian. The inclusion of a tender portrait of an elderly Vietnamese male among his photographs of the war in Vietnam is also very telling.

With McCullin’s pictures, content understandably dominates. This means we do not always address their extraordinary formal brilliance. His pictures bring the grace and beauty associated with Henri Cartier-Bresson’s ‘decisive moment’ into war zones. There is a lyrical aspect to many as he responds to the expressive power and force of gestures of suffering and grief. On occasion he also registers jubilation—for example, the portrait of the young stone thrower in Derry, caught mid-air as he jumps with joy, hands uplifted and face beaming, as he addresses his triumph to a youth standing before him. It is distinct from earlier pictures of protests on the streets in the UK, where protestors use their bodies as resistance as they are pictured blocking the street or being dragged by the police.

As well as highlighting McCullin’s extensive work abroad, the exhibition also draws attention to the importance of his documentary work in the UK in the 1960s and 1970s. There are portraits of the homeless men and women he had formed a connection with in London’s East End and there are photographs that indict the bad housing and poverty in both London and the North—photographs of what he has referred to as “social conflict”.

Brought up in working-class London’s East End he said he experienced the poverty he pictured and how the world he revealed was not alien to him. He often salvages traces and glimpses of humanity amidst the ruins and wreckage: a girl smiles with a cart laden with washing, against a backdrop of scrapped cars. In his picture of a mother and two children standing by the door of their dilapidated home in Brick Lane, daubed with paint with misspelt racist abuse, the disgusting message and run-down building jars with the tenderness and dignity of his portrait of the family.

McCullin’s pictures can often rest upon cruel contradictions and absurdities. In a scene of horror from Beirut in 1976, a group of young Phalangist fighters, one strumming a mandolin, appear to rejoice amidst the slaughter, a singing troupe indifferent to the remains of the dead Palestinian girl before them.

Among the searing pictures from the humanitarian crisis in Biafra, he offers a blunt variant of the Madonna and Child icon, turned into an atrocity image as the child seeks succour from the withered breasts of its starving, young but prematurely aged, mother. Here the holy family is evoked only to be violently sundered, a darkly ironic allusion from the hell on earth that war had created. McCullin made posters from this picture and fly posted them around London as a wake-up call to the British government’s arming of the federal military government in the civil war that caused the famine. Unlike many famine images, the woman in McCullin’s photograph is not passive in her suffering. She looks us straight in the eye.

It was Rupert Murdoch’s takeover of The Times in 1981, and the refusal of permission to be allowed to cover the Falklands War the following year, that marked the beginning of the end of McCullin’s extraordinary career as a photojournalist. The ends of his central activity as a photojournalist meant he started to take pictures of landscape, in Somerset, where he made his home and still lives, and also Scotland and Northumbria. The photographs are made mainly in winter time, when the landscape is stripped back, not bucolic, but spare, harsh and dramatic. For all their bleakness and darkness, his landscapes were for him a form of meditation and healing.

Beginning in the early 2000s, he embarked on pictures of the architectural remains of the Roman Empire, Southern Frontiers, in the North African and Levantine coastal countries of the Mediterranean. In turning to the sublime grandeur of these historical ruins—rendered through the darkness of heavy shadows and skies—he did not manage to escape the wars of the present. He photographed the ruins in Palmyra, Syria, before they were partly destroyed by Islamic State fighters, and returned in 2017 to picture what remained.

The landscapes in Britain and Southern Frontiers occupy the final rooms of the retrospective. We see them after seeing all the horrors that McCullin has photographed—an aesthetic reward, of sorts. But at the same time this turn to the pictorial, is not that far removed from what came before. Pictorial form has always been central to his photography.