The 81st Brigade was a formation of the British Army. It was originally formed from regular army battalions serving away from home in the British Empire. It was assigned to the 27th Division and served on the Western Front and the Macedonian Front during the First World War.
Formation
The infantry battalions did not all serve at once, but all were assigned to the brigade during the war.
References
81st Brigade (United Kingdom) Wikipedia(Text) CC BY-SA