ML 3-inch mortar

The ML 3-inch mortar is a conventional Stokes-type mortar that is muzzle-loaded and drop-fired. It also reuses many of the Brandt mortar features.^[2]

Based on their experience in World War I, the British infantry sought some sort of artillery for close support. The initial plan was for special batteries of artillery, but the cost was prohibitive and the mortar was accepted instead.

The Mark II mortar (Mark I was the Stokes) was adopted by the British Army in the early 1930s; and this was the standard British mortar when World War II broke out in September 1939. Experience in the early part of the war showed that, although the Mark II was reliable and sturdy, it did not have sufficient range compared to the German 81 mm s.GW.34 mortar. A series of experiments and trials using new propellants improved the range from 1,600 to 2,800 yards (1,500 to 2,600 m) by about 1942; and, by 1943, the barrel, baseplate and sights had also been improved.^[2][3]

The ML 3-inch mortar was carried on three packs by infantry or on Universal Carriers.^[3]

The Mark II remained in service with the British Army until replaced by the L16 81mm mortar in 1965.

• Mark 4 - heavier baseplate and new sight
• Mark 5 - lightened for use by airborne units and in the Far East
• The Canadian Army modified some of its 3-inch mortars, lengthening them to increase their range. This modification was abandoned as it was considered too heavy.
• The Australian Army, for its part, shortened the barrel for use in jungle.^[3]

• Afghanistan: used by the anti-Soviet insurgents in the 1980s^[4]
• Australia^[5]
• Biafra^[6]
• Canada^[5]
• Egypt^[7]
• Greece
• India^[8]
• Iraq^[9]
• Ireland^{[citation needed]}
•  Italy (1944–1946)^{[citation needed]}
• Jordan^[10]
• Luxembourg^{[citation needed]}
• Myanmar — Inherited from British-Burma Army and also bought from India. Main medium mortar used by the Myanmar Army till 1970s.^[11]
• New Zealand^[5]
• Nigeria^[12]
• Pakistan^[13]
• Philippines^{[citation needed]}
•  Poland — Used by the Polish Armed Forces in the West^[14]
• South Yemen^[15]
• Tibet^{[citation needed]}
•  United Kingdom^[5]
• Yugoslavia — Used by Yugoslavian Partisans^[16]

• Second World War
• Indo-Pakistani War of 1947–1948^[13]
• 1948 Arab–Israeli War
• Korean War
• Suez Crisis^[17]
• Sino-Indian War^[8]
• Nigerian Civil War
• Soviet-Afghan War

• Stokes mortar : British WWI predecessor
• List of infantry mortars

Weapons of comparable role, performance and era

• 8 cm Granatwerfer 34 – German WWII equivalent
• 82-BM-37 & 82-PM-41 – Soviet WWII equivalents
• Brandt Mle 27/31 – French WWII equivalent
• M1 mortar – US WWII equivalent
• Type 97 81 mm infantry mortar – Japanese WWII equivalent

• 
  Munitions workers being shown how to fire the 3-inch mortar on a range in 1943. Their factory had produced one million mortar bombs.
• 
  A mortar crew from the Queen's Own Royal West Kent Regiment in action in Tunisia, 31 January 1943.
• 
  The Queen's Own Cameron Highlanders training at Mena Camp near Giza, Egypt, 4 June 1940.
• 
  Pack horse carrying a 3-inch mortar of the Highland Light Infantry, Scotland, 7 May 1943.
• 
  Troops assemble a 3-inch mortar during anti-invasion exercises in Southern Command, 7 May 1941.
• 
  Norwegian troops with 3-inch mortars, Coatbridge, Scotland, 10 November 1940.