The Northumbrian Division mobilised on the outbreak of World War I in August 1914 and in April 1915 was sent to join the British Expeditionary Force on the Western Front, where it was numbered as the 50th (Northumbrian) Division. The division was immediately sent into action in the Second Battle of Ypres, and was engaged in many of the major actions on the Western Front for the rest of the war, including the later stages of the Battle of the Somme, the Battle of Arras, and the last phase of the Battle of Passchendaele. The division was virtually destroyed during the German spring offensive of 1918. The Divisional RE remained with the 50th while it was reconstituted with units brought back from other fronts. The division re-entered the line for the last month of the Allies' victorious Hundred Days Offensive. It was demobilised in March 1919.