Editing Town-class cruiser (1936) (section)

==Armament==
[[File:HMS Sheffield 6 inch turret 1941 IWM A 4401.jpg|thumb|left|Mk XXII turret with rounded contours mounted on the ''Southampton'' sub-class]]
Like their US and Japanese counterparts, the Town-class cruisers were "light cruisers" in the strict terms of the London Treaty, which defined a "light cruiser" as one having a main armament no greater than {{cvt|6.1|in}} calibre. All three naval powers sought to circumvent the limitations on heavy cruiser numbers by building light cruisers that were equal in size and effective power to [[heavy cruiser]]s. These ships made up for their smaller calibre guns by carrying more of them.

All ships of the class carried [[BL 6 inch Mk XXIII naval gun|BL 6-inch Mk XXIII guns]] in triple turrets, with the centre gun mounted {{cvt|30|in|abbr=on}} behind the two outer guns to prevent interference between the shells in flight and to give the gunners more room to work in.<ref>DiGiulian.</ref> The turret roofs had cutouts at the front to allow extreme elevation, originally intended to give the guns an [[Anti-aircraft warfare|anti-aircraft capability]]. In practice the guns could not be trained or manually loaded quickly enough for continuous anti-aircraft fire, so the Royal Navy designed the [[HACS#The Auto Barrage Unit|Auto Barrage Unit]] (ABU) which allowed the guns to be loaded with time-fuzed shells and then fired when the target aircraft reached a set range. These ships were equipped with the [[HACS]] AA fire control system for the secondary armament and the [[Admiralty Fire Control Table]] for surface fire control of the main armament.

[[File:HMS Belfast 3 db.jpg|thumb|left|Mk XXIII turret with squared-off contours mounted on the ''Edinburgh'' sub-class]]
The secondary armament consisted of four twin [[QF 4-inch naval gun Mk XIX|Mk XIX 4-inch]] turrets, and two [[QF 2-pounder naval gun|2-pounder quad pom-poms]].<ref name=friedman/> Additional light anti-aircraft weapons were added during the war and the 4-inch mounts were converted to [[Glossary of British ordnance terms#RPC|Remote Power Control]] (RPC).<ref name=friedman/> Postwar {{HMS|Birmingham|C19|6}} and {{HMS|Newcastle|C76|2}} were partially reconstructed in 1949–1951 with enclosed bridges, new [[lattice mast]]s, improved surface fire control, long range radar and an improved but still unreliable version of the Glasshouse Directors with Type 275 'lock and follow' radar, with flyplane control for the twin 4-inch guns with elevation speed increased to 15–20 degrees per second to engage faster jet aircraft.<ref name=friedman>Friedman 2013</ref> Similar electronic alterations were made to {{HMS|Sheffield|C24|2}} but it received less structural alteration. {{HMS|Liverpool|C11|2}} was put into reserve in 1952 to preserve it for potential modernisation and {{HMS|Glasgow|C21|2}} had a less extensive refit to allow her to be sent quickly if needed in the Suez crisis of 1956. ''Birmingham'', ''Newcastle'' and ''Sheffield'' had the pom-pom and 20&nbsp;mm armament replaced by [[Bofors 40 mm L/60 gun|40 mm Bofors]] mounts.<ref name=friedman/> ''Belfast'' was fitted with MRS 8 HACDT to combine 40&nbsp;mm and twin 4-inch AA fire and to permit the use of 40&nbsp;mm proximity fuze ammunition as used by the [[British Army]].