21st Division (United Kingdom)

The British 21st Division was a New Army division raised in September 1914. 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. 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.

Formation

 * 62nd Brigade:


 * 12th (Service) Battalion, Northumberland Fusiliers
 * 13th (Service) Battalion, Northumberland Fusiliers
 * 8th (Service) Battalion, The East Yorkshire Regiment (until November 1915)
 * 1st Battalion, The Lincolnshire Regiment (from November 1915)
 * 10th (Service) Battalion, Alexandra, Princess of Wales's Own (Yorkshire Regiment) (disbanded February 1918)
 * 2nd Battalion, The Lincolnshire Regiment (from February 1918)
 * 3/4th Battalion, The Queen's (Royal West Surrey Regiment) (from August 1917)


 * 63rd Brigade:

In July 1916 the brigade moved to the 37th Division, swapping with the 110th Brigade.


 * 8th (Service) Battalion, The Lincolnshire Regiment
 * 8th (Service) Battalion, Somerset Light Infantry
 * 12th (Service) Battalion, The Prince of Wales's Own (West Yorkshire Regiment) (until November 1915)
 * 4th Battalion, The Duke of Cambridge's Own (Middlesex Regiment) (from November 1915)
 * 10th (Service) Battalion, The York and Lancaster Regiment


 * 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 (until November 1915)
 * 15th (Service) Battalion, Durham Light Infantry
 * 1st Battalion, The East Yorkshire Regiment (from November 1915)


 * 110th Brigade:

In July 1916 the brigade joined from the 37th Division, swapping with the 63rd Brigade.


 * 6th (Service) Battalion, The Leicestershire Regiment
 * 7th (Service) Battalion, The Leicestershire Regiment
 * 8th (Service) Battalion, The Leicestershire Regiment (until June 1918)
 * 9th (Service) Battalion, The Leicestershire Regiment (disbanded February 1918)
 * 1st Battalion, The Duke of Edinburgh's (Wiltshire Regiment) (from June 1918)


 * Pioneers:


 * 14th (Service) Battalion, Northumberland Fusiliers

Battles
The division took part in the Battle of Loos, Battle of the Somme, Battle of Arras, Battle of Passchendaele and Battle of Cambrai.