Peacetime procurement and a balanced fleet

A war with Japan was one contingency for which the Royal Navy's major units were comparatively useful, while the Battle of the Atlantic exposed its shortage of quickly built escorts. Different missions require a balanced fleet rather than a zero-sum choice between battleships, carriers, cruisers, and small vessels. Major warships take years to complete, whereas wartime pressure can redirect yards toward simpler escorts only after the shortage has become dangerous. The same force-mix problem appears on land: armoured personnel carriers are cheaper, faster, and more versatile, but they cannot do the work of a main battle tank when heavy armour is needed. The hypothetical interwar programme calls for roughly 40 treaty-exempt sloops a year from 1920, potentially creating a force of about 360 by World War II. Fitted with four-inch anti-aircraft guns, ASDIC, depth charges, and light weapons, those ships could provide the first escort layer for convoys while capital ships and cruisers covered the missions that only major units could perform.