British1st Division was a permanently established Regular Army division that was amongst the first to be sent to France at the outbreak of the First World War. It served on the Western Front for the duration of the war After the war the division was part of the occupation force stationed at Bonn.
The division's insignia was the signal flag for the 'Number 1'.
10th (Service) Battalion, The Gloucester Regiment (until February 1918)
8th (Service) Battalion, The Royal Berkshire Regiment (until February 1918)
1st Battalion, The Loyal North Lancashire Regiment (from 2nd Brigade _ February 1918)
Originally called the '1st (Guards) Brigade' because it contained the 1st Battalions of the Coldstream Guards and the Scots Guards. When the Guards Division was formed in August 1915 and these two battalions departed, the brigade was redesignated.
2nd Brigade
2nd Battalion, The Royal Sussex Regiment
1st Battalion, The Loyal North Lancashire Regiment (to 1st Brigade - February 1918)