Apron screens came into use shortly before the end of the First World War in response to attacks by German Gotha bombers on London. They consisted of three balloons, 500 yards apart, joined together by a heavy steel cable. No enemy aircraft were actually caught in their nets but they did force enemy aircraft to fly higher, reducing their effectiveness as bombers and making them morevulnerable to attack.The possibility of a painting of the barrage balloon apron was raised by Charles Foulkes, secretary and curator of the Imperial War Museum, after a visit to the Thames estuary in August 1918, and Dobson was suggested to paint it. 'A very interesting record will be the Balloon Barrages which go up in the evening as a protection to Kynoch's Factory, on Canvey Island. . . and the most effective time would be Evening or late sunset effect,' he wrote. Kynoch's were one the leading suppliers of ammunition and explosives during the war and an obvious target for bombing.Problems arose with the painting because the somewhat conventionally-minded Air Force committee did not approve of the style, although they agreed that it was technically accurate. As a result, the idea for a picture from Dobson was dropped. An earlier commission with theMinistry of Information had been terminated for similar reasons - 'I don't seem to have much luck with official work,' he wrote.