Bomberg’s harrowing service in the trenches during the First World War was compounded by a disastrous experience as a war artist. In 1917 he was commissioned by the Canadian War Memorials Fund to commemorate an incident in which a company of Canadian soldiers dug tunnels under the German trenches to lay explosives for a surprise assault on the enemy defences at Ypres, in France. In preparation for his painting of the sappers at work, he made a series of drawings. Here, his tiny figures are dwarfed by the dominant, complex structures of struts, girders and pulleys that formed part of the underground environment, conveying a sense of the enormity of their task and the claustrophobic atmosphere of the tunnels.