The L9A1 51 mm light mortar was a man-portable mortar system used by the British Army. Smoke, illuminating and high explosive bombs are available. A short range insert device allows the weapon to be used in a direct fire mode. The 51 mm mortar, which replaced the World War II-vintage 2 inch mortar, was due to be phased out by the use of the 40 mm L17A2 UGL (underslung grenade launcher) mounted on the L85A2; however operational experience has led to the decision to replace it with a 60mm Mortar. The M6-895 60 mm Mortar has been procured as an Urgent Operational Requirement (UOR) to replace the current 51 mm Mortar on current operations.
Ammunition for the 51 mm mortar has a small, ring-pull safety pin on the side of the nose-fuze. The fuze remains unarmed until the pin is withdrawn. Therefore, the safety pin must always be removed and discarded before a mortar shell is fired.