5920664 17th (1st Football) Battalion Middlesex Regiment, 1915 circa (b/w photo) by Unknown photographer, (20th century); National Army Museum, London; (add.info.: 17th (1st Football) Battalion Middlesex Regiment, 1915 circa. Photograph, World War One (1914-1918), 1915 circa. The formation of the ?New Armies? during World War One allowed footballers to enlist en masse in ?Pals\' Battalions?. Clapton Orient (now Leyton Orient FC) were the first English Football League club to enlist together. They joined the 17th Battalion of the Middlesex Regiment, which was known as the ?Footballers\' Battalion?. One of nine photographs collected by Lieutenant Scotland, 17th (1st Football) Battalion Duke of Cambridge?s Own (Middlesex Regiment), 1915 circa.); by National Army Museum .