As students the group forged links with the artistic avant-garde-the Futurists, the Vorticists and the Bloomsbury Group-but war did away with their theoretical chatter and concentrated the mind. Paul Nash and C.R.W. Nevinson in particular went on to become painting's equivalents of Wilfred Owen and Edward Thomas. It was Nash from the frontline who expressed their role as witnesses: "I am a messenger who will bring back word from the men who are fighting to those who want the war to go on for ever. Feeble, inarticulate, will be my message, but it will have a bitter truth, and may it burn their lousy souls."

Relations between the artists were not always smooth: Mark Gertler, for example, had a long and unrequited infatuation with Dora Carrington and fell out with his erstwhile best friend Nevinson when he too fell in love with her. Gertler would survive the war and become the model for Loerke in D.H. Lawrence's Women in Love before committing suicide in 1939, partly due to depression induced by Carrington's own suicide. The personal links between the painters are part of the exhibition, which includes letters and photographs as well as paintings such as Stanley Spencer's Unveiling Cookham War Memorial (1922), which has not been on display for 25 years.

This is not, however, an exhibition of war art but rather of painters forced by circumstances into becoming war artists. Indeed the show is underpinned by a shared yearning for pastoral-Gertler's The Fruit Sorters, Spencer's Apple Gatherers, Carrington's The River Pang, Nash's The Sea Wall-that makes the out-of-frame presence of the war all the more menacing.