was the main gun of a tank; this was very important when a tank was being used for infantry support, leaving it with only its machine gun for anti-personnel use. A high-explosive shell was not produced until late 1942. Service history The 2-pdr gun became a part of the Royal Artillery in 1938, when five field brigades were converted to anti-tank regiments. In the early western campaigns, the 2-pdr was employed by two types of Royal Artillery formations: anti-tank regiments of infantry divisions (four batteries with 12 pieces each), and light anti-aircraft/anti-tank regiments of armoured divisions (two 12-gun AT batteries). From October 1940, separate 48-gun anti-tank regiments were introduced in armoured divisions too. Infantry brigade structure initially included an anti-tank company, though it was typically equipped with 25 mm Hotchkiss anti-tank guns; these companies were disbanded later in the war. From 1942, infantry battalions received their own six-gun anti-tank platoons. The organization was different in the Far East theatres. The exact internal structure of AT units was also subject to changes and variations. The gun first saw combat with the British Expeditionary Force (World War II) during the German invasion of the Low Countries and the subsequent rear-guard actions at Dunkirk. Most of the British Army's 2-pdrs were left behind in France during the retreat, stripping most of the army's infantry anti-tank capability. Those guns captured at Dunkirk entered German service under the designation 4.0 cm Pak 192 (e) or 4.0 cm Pak 154 (b), the "e" and "b" referring to the origin (English or mistakenly attributed to the Belgian Army). Although Woolwich Arsenal had already designed a successor to the 2-pdr, the 6 pounder gun, it was decided in the face of a possible German invasion to re-equip the army with the 2-pdr, avoiding the period of adaptation to production, and also of re-training and acclimatization with the new weapon. Consequently, 6 pounder production was delayed until November 1941 and frontline availability until spring 1942. Thus during most of the North African Campaign the army had to rely on the 2-pdr, augmented by the 25 pounder gun-howitzer functioning as an anti-tank gun—a role for which it was capable (at the expense of diverting it from its main artillery role). As German tank design evolved, anti-armour performance of the 2-pdr gradually became insufficient; however, the gun owes a large part of the bad reputation it gained during the campaign to