During World War One Great Britain suspended construction of capital ships but continued to build cruisers. Most of these were designed to serve as scouts for the Grand Fleet with a short radius of action, sufficient for North Sea operations but insufficient for operation requiring a longer reach, such as protection of trade routes. The war bankrupted the British government and both army and navy were drastically slashed to greatly reduce their expense. Most of the prewar and war built cruisers were worn out and had a short range, so only the later war-built construction was retained. The E class was the last of the British cruiser designs to be developed during the war. Designed after the heavier Elizabethans of the Hawkins class, the ships were designed to combat an opponent who was never built. Rumors came into the Admiralty that the Germans were building new large light cruisers, so the E class was designed to combat these wraiths. They were large cruisers, displacing 7,550-tons and armed with seven single gun 6-inch Mk XII guns. Provided with machinery developing 80,000shp, they were capable of 33 knots. HMS Enterprise was laid down in June 1918 and HMS Emerald on September 23, 1918. Since the war came to and end a few months later, the construction of these two were put on hold and an order for a third class, the Euphrates was cancelled. After launching the hulls were towed to Royal Dockyards for completion. For seven years work was done on an on and off status, reflecting a building pattern more in tune with a navy of a banana republic, rather than the Royal Navy. Finally both were completed in 1926.
Because of their larger size and newness of construction, they were retained as the Royal Navy belatedly started to scramble to prepare for World War Two. They were large enough to have catapults for observation aircraft added, as well as raising the fore-funnel and adding HAC directors for AA gunfire. There were plans to convert the pair to full AA cruisers with replacement of the 6-inch guns with twin 4-inch DP mounts and multiple pom-pom mounts. However, the arrival of World War Two cancelled this plan. Emerald received two quadruple .50 Vickers machine gun mounts but these were rather ineffectual. From August 1942 to April 1943 she underwent a long refit which landed two aft 6-inch guns, single 40mm guns and the quad Vickers MG mounts and added two quadruple pom-poms and six twin power operated 20mm mounts. In April 1944 a further refit landed the catapult and added six 20mm single Oerlikons. From commissioning Emerald spent most of her time in the far east. In September 1939 she was with the 12th Cruiser Squadron on Northern Patrol duties. In 1940 she spent her time on convoy duty. In 1941 she was transferred to the east for escort duties in the Indian Ocean and remained as part of the Fast Group of the Royal Navy force in the Indian Ocean for the start of the war in the Pacific. She returned to England for a refit in August 1942. She was back in the east by April 1943. In 1944 she returned to the Atlantic and supported Juno Beach Operations on D-Day. She was placed in reserve in January 1945 and in 1947 was selected for target trials. As a result she sank on October 24, 1947 but was raised in June 1948 just to get her to the breakers later that month.
Neptun Model produces a 1941 fit of HMS Emerald N-1147 before the addition of the pom-poms and twin 20mm mounts.