The first day of the Somme was a complete failure, and saw nearly 60,000 casualties being sustained by the British Army, the bloodiest day in British military history. The diversionary assault at Gommecourt was also considered a failure, sustaining only heavy casualties for both divisions involved, with 56th Division suffering 4,567 men and 182 officers killed, wounded or missing. The division later participated in the pursuit of the German Army when they retreated to the Hindenburg Line in early 1917, and later in battles at Arras, Langemarck, Passchendaele, Cambrai, Albert, Spring Offensive, and the Hundred Days Offensive, suffering heavy casualties in nearly all engagements. By the time of the Armistice of 11 November 1918 the division had sustained nearly 35,000 casualties in just over two and a half years. The brigade was composed as follows during the war:  Due to a shortage of manpower in the BEF in early 1918, all British divisions serving on the Western Front were reduced from twelve to nine infantry battalions, with all brigades reducing to three. The 1/9th Londons (the only original battalion of the brigade) were, therefore, transferred from 169th Brigade to 175th (2/3rd London) Brigade of 58th (2/1st London) Division where they were amalgamated with the 2/9th Londons and was subsequently renamed the 9th Battalion. On 6 February, with the disbandment of 2/5th Londons, the 1/5th was redesignated as the 5th Battalion. The Territorial Force was disbanded after the war but later reformed in 1920 as the Territorial Army, formed on a very similar basis to the old Territorial Force. The brigade was reformed as the 169th (3rd London) Infantry Brigade, along with the rest of the division, with much the same composition it had before the Great War, of four Territorial battalions of the London Regiment. In 1922 all battalions of the London Regiment dropped the 'battalion' from their title, becoming, for example, 9th London Regiment (Queen Victoria's Rifles). Throughout the inter-war years 169th Brigade, unlike the other two brigades of 56 Division, saw little change in its composition until the middle part of the 1930s. In 1935 the 10th London Regiment (Hackney) was transferred as a replacement battalion to 167th (1st London) Infantry Brigade. Due to a serious need to strengthen the anti-aircraft defences of the United Kingdom, particularly for London, Southern England and the Midlands, many infantry battalions of the Territorial Army were, throughout the 1930s, converted into anti-aircraft or searchlight battalions of either the Royal Artillery or Royal Engineers.