In 1914, at the start of the First World War, Novello wrote "Keep the Home Fires Burning", a song that expressed the feelings of innumerable families sundered by World War I. Novello composed the music for the song to a lyric by the American Lena Guilbert Ford, and it became a huge popular success, bringing Novello money and fame at the age of 21. In other respects, the war had less impact on Novello than on many young men of his age. He avoided enlistment until June 1916, when he reported to a Royal Naval Air Service (RNAS) training depot as a probationary flight sub-lieutenant. After twice crashing an aeroplane, Marsh arranged his move to the Admiralty office in central London for the rest of the war.