Stokes mortar
The Stokes mortar was a British trench mortar invented by Sir Wilfred Stokes KBE that was issued to the British, Commonwealth and U.S. armies, as well as the Portuguese Expeditionary Corps (CEP), during the later half of the First World War. The 3-inch trench mortar is a smooth-bore, muzzle-loading weapon for high angles of fire. Although it is called a 3-inch mortar, its bore is actually 3.2 inches or 81 mm.
Design
Frederick Wilfred Scott Stokes – who later became Sir Wilfred Stokes KBE – designed the mortar in January 1915. The British Army was at the time trying to develop a weapon that would be a match for the Imperial German Army's Minenwerfer mortar, which was in use on the Western Front.
Stokes's design was initially rejected in June 1915 because it was unable to use existing stocks of British mortar ammunition, and it took the intervention of David Lloyd George (at that time Minister of Munitions) and Lieutenant-Colonel J. C. Matheson of the Trench Warfare Supply Department (who reported to Lloyd George) to expedite manufacture of the Stokes mortar.