HC “Cookie” Bomb Mk IV

The 4,000 lb HC “Cookie” Bomb Mk IV was a British high-capacity explosive developed from the earlier Mk I. Unlike the Mk I—which used one No. 13 Mark I pistol in the nose and two No. 30 Mark II pistols in the body—the Mk IV used three No. 27 Mark I pistols mounted in the nose, improving reliability and simplifying arming procedures. In addition to using the Avro Lancaster bomber as the primary delivery vehicle, modified Mosquito B Mk IV Series II aircraft were adapted with bulged bomb bays to carry this bomb internally, enabling high-speed, precision night raids as part of the RAF’s Light Night Striking Force. This pairing combined the Mosquito’s agility with the Cookie’s destructive power, allowing surgical strikes on hardened or urban targets with minimal exposure to enemy defenses. The Mk IV’s improved fuze configuration and compatibility made it a more versatile and dependable weapon in the RAF’s strategic arsenal.