On 13 May 1915 the division was numbered, becoming the 48th (South Midland) Division and the brigades in the division were also numbered, the 1st Warwickshire Brigade became the 143rd (Warwickshire) Brigade. The brigade served throughout the Great War on the Western Front in battles at the Somme and Passchendaele. In early November 1917 the 143rd Brigade, with the rest of 48th (South Midland) Division, was sent to the Italian Front and fought at Piave River in June 1918 and later at Vittoria Veneto, which ended the war in Italy with the signing of the Armistice of Villa Giusti. Both the brigade and division ended the war in Italy.