The 21st Division was an infantry division of the British Army during World War I, raised in September 1914 by men volunteering for Lord Kitchener's New Armies. The division moved to France in September 1915 and served on the Western Front for the duration of the First World War. The division's insignia was the "triple-seven". Unit history The Division was the first of the six created for the Third New Army on 13 September 1914. It moved to France in September 1915. It took part in the Battle of Loos in September 1915, the Battle of the Somme in autumn 1916, the Battle of Arras in April 1917, the Battle of Passchendaele in autumn 1917 and the Battle of Cambrai in November 1917. The division suffered 55,581 killed, wounded and missing, being the highest number of casualties suffered by any New Army division. The Division ceased to exist on 19 May 1919. Order of battle The following units served with the division: 62nd Brigade 12th (Service) Battalion, Northumberland Fusiliers (renamed 12th/13th battalion in August 1917) 13th (Service) Battalion, Northumberland Fusiliers (merged with 12th Northumberland Fusiliers in August 1917) 8th (Service) Battalion, East Yorkshire Regiment (left November 1915) 1st Battalion, Lincolnshire Regiment (joined November 1915) 10th (Service) Battalion, Alexandra, Princess of Wales's Own (Yorkshire Regiment) (disbanded February 1918) 3/4th Battalion, Queen's (Royal West Surrey Regiment) (joined August 1917 disbanded 11 February 1918) 2nd Battalion, Lincolnshire Regiment (joined February 1918) 62nd Machine Gun Company (joined 4 March 1916, transferred into 21st MG Battalion 24 February 1918) 62nd Trench Mortar Battery (joined by 16 June 1916) 63rd Brigade In July 1916 the brigade moved to the 37th Division, swapping with the 110th Brigade. 8th (Service) Battalion, Lincolnshire Regiment 8th (Service) Battalion, Prince Albert's (Somerset Light Infantry) 12th (Service) Battalion, Prince of Wales's Own (West Yorkshire Regiment) (until November 1915) 4th Battalion, Duke of Cambridge's Own (Middlesex Regiment) (from November 1915) 10th (Service) Battalion, York and Lancaster Regiment 63rd Machine Gun Company (joined 4 March 1916) 63rd Trench Mortar Battery (joined 16 June 1916) 64th Brigade 9th (Service) Battalion, King's Own (Yorkshire Light Infantry) 10th (Service) Battalion, King's Own (Yorkshire Light Infantry) (disbanded February 1918) 14th (Service) Battalion, Durham Light Infantry (left November 1915) 15th (Service) Battalion, Durham Light Infantry 1st Battalion, East Yorkshire Regiment (joined November 1915) 2nd Battalion, South Lancashire Regiment (attached 21 to 30 June 1918) 64th Machine Gun Company (joined