While the 3.7-inch was the main HAA gun in fixed defences and the only mobile HAA gun with the field army, the QF 4.5-inch gun, manned by artillery, was used in the vicinity of naval ports and made use of the naval ammunition supply. The 4.5-inch at Singapore had the first success in shooting down Japanese bombers. Mid war QF 5.25-inch naval guns started being emplaced in some permanent sites around London. This gun was also deployed in dual-role coast defence/AA positions.
While the 3.7-inch was the main HAA gun in fixed defences and the only mobile HAA gun with the field army, the QF 4.5-inch :gun, manned by artillery, was used in the vicinity of naval ports and made use of the naval ammunition supply. ?The 4.5-inch at Singapore had the first :success in shooting down Japanese bombers. Mid war QF 5.25-inch naval guns started being emplaced in some permanent sites aro!und London. This gun was also deployed in dual-role coast defence/AA positions.