In June 1917, and holding the temporary rank of general, Byng took command of Britain's largest army, the Third Army, until the cessation of hostilities and, with those troops, at the First Battle of Cambrai, conducted the first surprise attack using tanks. The Battle of Cambrai was later considered a turning point in the war and Byng was honoured on 24 November 1917 by having his temporary rank of general made substantive; however according to the World War I memoir of A S Bullock, the First Battle of Cambrai failed to breach the Hindenburg Line, due to lack of reserves, and it was at General Byng's second attempt to take Cambrai in 1918 that the British triumphed, owing to sufficient troops and supplies being in place 'to sustain the attack day and night until the Germans were broken'.