An early 5.25-inch dual-purpose gun standardizes the Royal Navy

What if Britain began developing a successful 5.25-inch dual-purpose naval gun in 1925?

A satisfactory gun could become a fleet standard, with two twin mounts on sloops and three twin mounts plus ten torpedoes on destroyers.

The result depends on Britain producing a satisfactory dual-purpose 5.25-inch gun from 1925. That would leave enough time to develop a suitable mounting and make the weapon common across the fleet during the 1930s. It could replace several smaller gun families on destroyers and sloops as well as larger ships. Sloops could carry two twin mounts, one forward and one aft. A likely destroyer arrangement would use three twin dual-purpose mounts and ten torpedoes, producing something resembling the later Daring concept.