EXHIBITIONS / Martial art: In art and war, the painter Rex Whistler was a helpless romantic. Iain Gale on a life of innocence and experience

His body was unmarked. The blast from the mortar bomb had thrown him high into the air and broken his neck. In death, as in his life and art, Rex Whistler was flawless. For the previous 20 years Whistler, who is the subject of an exhibition which opened in London yesterday, had delighted British society with paintings in a style which married the excesses of the high Baroque with the wry Englishness of Hogarth, Gillray and Bateman. So popular was he that the Times's obituaries received more correspondence about Whistler than anyone else killed during World War Two.

Born in 1905, Whistler showed early promise. By the age of 22 his style was fully matured. The pictures he painted in 1927 for the Tate Gallery's Refreshment Room differ little from those of his last years when, as an officer in the Welsh Guards, he continued to work as an artist.

From the outbreak of war, Whistler had been desperate to secure a commission and the self-portrait he painted in May 1940, wearing the uniform of a Guard's lieutenant, was a celebration of his new-found role. Whistler shows himself surrounded by the accoutrements of his double-life as painter and paladin. On a chair lie his officer's hat and gloves, while, beside him he has carefully placed a pile of brushes, tied with a piece of camouflage netting, but looking, for all the world, more like the thunderbolts of some Baroque Jupiter.

It was chiefly as the painter of such portraits that Whistler had become the darling of the haut monde in the early 1930s. During the war, while his battalion remained in Britain, awaiting the second front, he passed his leave in the homes of the great and good producing such works as his charmingly informal Portrait of Lady Studholme, painted in 1942. In barracks, however, Whistler found his brother officers inclined rather to the more robust style which he had perfected as an illustrator of books and stage designs for the International Ballet Company, the Westminster Theatre and others. When his battalion was condemned to make its officers' mess in a Nissen hut at Codford, Whistler brightened up its walls with trompe-l'oeil swags and medallion portraits of the officers. Billeted in Brighton, he decorated the sitting-room wall with his now famous allegory of The Prince Regent Awakening the Spirit of Brighthelmstone.

Whistler stands in a tradition of artist-soldiers which includes Michelangelo and the Impressionist Bazille. That soldiering appealed to his love of finesse is shown in his meticulous drawing of how the soldier should lay out his kit for inspection. But there is more to Whistler's art than an obsession with fine workmanship and more to his martial character than a man living out the imagined battles of his childhood drawings.

For Whistler, in 1944, war could still hold a passing glory. A romantic in life, Whistler died a romantic's death, leading his men in the first battle of his military career against an enemy he knew to be evil. In both his ideals and his art he seemed to encapsulate much of that Britain for which he and his fellows were fighting, and his death in Normandy, a month after D-Day, marked not only the passing of a talented artist, but also of an age of innocence.

National Army Museum, Royal Hospital Rd, London, SW3 (071- 730 0717). To 18 Sept