Hughie O'Donoghue's new exhibition explores his father's experiences as a soldier in the 1940s, writes Aidan Dunne

To get to Hughie O'Donoghue's exhibition Painting Caserta Red, at the Imperial War Museum in London, you have to make your way through a formidable array of wartime hardware. Past spruced-up examples of second World War tanks and artillery pieces and beneath suspended fighter aircraft in full livery, like gigantic toys. Remote from flesh and blood, from fear and death, the paraphernalia exerts a profound fascination. But two storeys up, in the cool oasis of the museum's art galleries, the war suddenly gets very personal.

The museum is fast building an impressive record in imaginative gallery programming, with a consistent focus on the realities underlying the human experience of warfare rather than specialised military history. And that is exactly what Painting Caserta Red is about. In more than 20 works, including several extremely large paintings, O'Donoghue chronicles and explores the repercussions of his father's experiences as a soldier, initially with the British Expeditionary Force in France and, subsequently, as part of the Eighth Army in Italy and Greece, right until his return home after the war, in 1946.

This outline makes the work sound as if it is an account of one man's war, which it both is and isn't. It is firmly grounded in the particularity of Daniel O'Donoghue's experience and draws freely on family photographs and correspondence. Often the photographs, greatly enlarged, are physically incorporated in the paintings. In Anabasis, a series of photographs is integrated into open volumes of Encyclopedia Britannica and overpainted. They form a chronological account of Daniel's experience from 1943 to demobilisation.

"Because it's personal," says O'Donoghue of the show's subject matter, "the assumption is that it must be about him. And of course it is about him, but the point is that it is also about anyone caught up in those circumstances, as people were, all over Europe. You go from the particular to the universal." Just as, conversely, the encyclopedia, that general repository of knowledge, is overwritten with a personal history.

Nor does the work chart a military campaign in any conventional sense. There are images of war: army motorcycles abandoned in the retreat to Dunkirk, a hellish vision of the ruins of Monte Cassino after prolonged bombardment, the corpse of a German soldier, tanks crossing the Rapido river and more. But on the whole they are, as O'Donoghue puts it, history paintings with very little reference to historical events in the way you'd expect.

"The works are bracketed around certain times and places during the war, that's the framework that holds them together," he says. "But I didn't want to make generalisations about things everyone knows about anyway. I wanted to look at everything that was part of the story, not just the epochal events." He wanted to reflect events through the truth of individual experience.

The paintings are steeped in references to classical European culture, which relates directly to Daniel's perceptions at the time. A voracious reader, he moved around Italy as an informed observer, always seeking out sites of antiquity, dispatching postcards home. For O'Donoghue, classical statuary, excavated from the earth during the Renaissance, is emblematic of a larger cultural memory within which we operate.

"I'm fascinated by the idea that underneath our feet there is a template that tells us who we are, where we came from. How we look at the past can unlock something in ourselves." Again and again his paintings return to the metaphor of excavation in this physical, archaeological sense. In fact it's more than a metaphor for him: it's part of the process.

"I believe in working through the image. I do excavate the surface. It's not an affectation; it has to do with the way some areas aren't working, so you have to burn them off or sand them down. Images are used, worked, lost, found again . . . . It all adds to the texture of things. All the pictures have a surface that is a map of their own making. They're worked over, like fields."

In the past he has drawn on the archaeological finds of preserved human remains in bogland as subjects. Here several works refer to the sinking of the heavily laden troopship Lancastria during the evacuation from France, and it seems likely that among the sources for some of the show's paintings of figures suspended in water is a nightmarish account of the way the bodies of the oil-covered survivors of the sinking were imprinted on the structure of the trawler that rescued them.

An additional point about the Lancastria is that news of the sinking was suppressed because it was regarded as potentially disastrous for public morale and so forms part of the hidden, invisible history that O'Donoghue is trying to unearth.

One of the recurrent classical images is that of a statue of the satyr Marsyas, a skilful flute player whose grisly fate, having lost a rigged contest with Apollo, was to be suspended from a tree and flayed alive. His sacrificial presence haunts several of the compositions and is echoed in a news photo of the bodies of Mussolini and several of his supporters suspended by their ankles and, in another photograph, of a German soldier whose skin has been seared from his skull. As it happens, Daniel played the flute, but he lost his instrument when he almost drowned crossing the Rapido.

Despite the references to the Lancastria, and despite a cruciform pose, there are more positive connotations to most of the paintings of the underwater swimmer, who is in ways a pendant to Marsyas.For O'Donoghue this is essentially an optimistic image of a body naked and unencumbered, momentarily free, an image about aftermath and hope. "It's an individual immersed in water but, equally, in thought, in hopes and aspirations at the end of the war; it's supposed to be sensuous, hedonistic."

The series of swimmers is entitled Baia, after the Bay of Baia, the Roman resort near Naples where Daniel swam. "Going through his photographs you realise that when soldiers took photographs they didn't take photographs of dead bodies and ruins, they took cheerful photographs of themselves relaxing." So there is an almost Arcadian quality to some of the images snatched during otherwise grim times. Yet despite his appreciation of places war brought him to, O'Donoghue points out, Daniel never returned to France, Italy or Greece.

It is fair to see The Tomb Of The Diver as a memorial to his father. It was in part inspired by the eponymous fifth-century tomb in southern Italy, which is thought to symbolise a leap into the unknown. The diver plunges between the Pillars of Hercules and so into the unknown vastness of the Atlantic Ocean and, perhaps, an afterlife. He may be, O'Donoghue also observes, an Icarus figure.

In making these works he posed problems for himself, to do with the ongoing dialogue between the photographic and the painted image and to the question of scale. The photographs are there emblematically as documents.

"I consciously used the photograph as a true image, based on trust or intention." The question of scale is also relevant to intention. "I was thinking about what a monument is. Something that remembers or records." These are certainly monuments, not to generals or statesmen but to "anyone, anytime".

• Painting Caserta Red by Hughie O'Donoghue is at the Imperial War Museum, London, until September 7th and the Imperial War Museum North, Manchester, from September 27th to January 18th