List of British weapon L numbers

The L number ("L" standing for Land Service) or weapon identity number system is a numerical designation system used for the type classification of British Army weapons and related stores. The L number in isolation is not a unique identifier; rather, it is used in conjunction with a description, e.g. "Rifle, 7.62mm, L1A1" or "L1A1 7.62mm Rifle". The A number following the L number refers to the particular version of a piece of equipment; unlike some similar designation systems where an A number is only used for subsequent versions of equipment, an A1 designation is always used for the first version to be officially adopted. Stores coming into Army service began receiving Land Service designations in 1954, replacing the old number-and-mark system of designations.

The L number system does not have universal application. Some items such as the AR-15 and M16A2 rifles, the C2A1 Sight Unit, the C3 Non-Metallic Anti-Personnel Mine and its C4 drill variant, the M18A1 Anti-Personnel Mine, the M79 and M203 grenade launchers, the M6-895 and M6-640 mortars, the Barrett M82, the M3 and M63 Browning M2 mounts, and the various air rifles in Cadet Force usage have been referred to in official documentation by their manufacturer's designations instead of L numbers. Likewise, legacy items that were given designations under the earlier number-and-mark system have continued to be referred to by those designations until their replacement by newer stores. A number of guided weapons in British service such as the K170A1/A2 NLAW HEAT Guided Missile and the K130 High Velocity Missile use a "K" designation rather than a Land Service one.

Equivalent designation systems were devised for the Royal Navy ("N", standing for Naval Service) and the Royal Air Force ("A", standing for Air Service), though in many cases stores shared with the Army have continued to be referred to by their Land Service designations; Land Service designations have also been used where no Army equivalent exists, as in the case of the Royal Navy's L44A1 Machine Gun. The FV (fighting vehicle) number series is similar in purpose but not in formatting. Similar designation systems are used by various other militaries; for example, Canada uses "C" (standing for Canadian), Australia uses "F" (standing for Forces), and several nations such as Denmark, South Africa, and the United States of America use or used "M" (standing for Model or its non-English equivalent).