In November 1941 Bush was conscripted into the army, and after initial training was assigned to the Royal Army Medical Corps. Based in London, he was given leave to perform in concerts, which enabled him to conduct the premiere of his First Symphony at a BBC Promenade Concert in the Royal Albert Hall on 24 July 1942. He also performed regularly with the London String Orchestra, and in 1944 was the piano soloist in the British premiere of Shostakovich's Piano Quintet. His wartime compositions were few; among them were the "Festal Day" Overture, Op. 23, written for Vaughan Williams's 70th birthday in 1942, and several songs and choruses including "Freedom on the March", written for a British-Soviet Unity Demonstration at the Albert Hall on 27 June 1943.