In 1914 the Germans, trying to break the stalemate of trench warfare, exploded mines under British positions at Festubert, in Belgium, inflicting terrible casualties. The British responded, recruiting professional miners, and by summer 1916 they had 33 companies of tunnellers at the Western Front.The tunnel at St Eloi was 1,650 feet long and 125 feet deep. It was used to explode the largest mine of the war. This was one of 19 mines exploded at the launch of the Messines offensive in June 1917 and helped the British 41st Division to capture the village.In 1918 David Bomberg, who had served in the Royal Engineers, was commissioned by the Canadian Government to paint the operation. Bomberg was a major figure in the London avant-garde, influenced by Cubism and Futurism. He reduced his subjects to geometric forms, full of tension and kinetic energy. The Canadians, however, asked him to avoid abstraction, and rejected his first painting as too Futurist. This work is a preparatory sketch for a second version, now in the National Gallery of Canada, Ottawa, in which Bomberg compromised and produced a more representational work. The tension and geometry that interested Bomberg are still evident in the complex rhythm of the beams against the curved tunnel walls and in the figures' poses, but the bright colour and bold abstraction of the first work have disappeared. Bomberg has included himself in the foreground of the picture carrying a heavy beam to show his feeling of being burdened by this task.