The s was a class of 32 destroyers of the Royal Navy that were launched from 1943 to 1945. The class was built in four flotillas of 8 vessels, the "Ca", "Ch", "Co" and "Cr" groups or sub-classes, ordered as the 11th, 12th, 13th and 14th Emergency Flotillas respectively. The sub-class names are derived from the initial two letters of the member ships' names, although the "Ca" class were originally ordered with a heterogeneous mix of traditional destroyer names. A fifth flotilla, the "Ce" or 15th Emergency Flotilla, was planned but were cancelled in favour of the s after only the first two ships had been ordered. The pennant numbers were all altered from "R" superior to "D" superior at the close of World War II; this involved some renumbering to avoid duplication.