The Type system is a classification system used by the British Royal Navy to classify surface escorts by function. The system evolved in the early 1950s, when the Royal Navy was experimenting with building single-purpose escort vessels with specific roles in light of experience gained in World War II. The original (July 1950) numbering scheme was: Type 1X were Anti-Submarine (ASW) frigates (when the numbers ran out in the 1960s, ASW frigates continued as the Type 2X series). Type 3X were General-Purpose (GP) frigates (Chosen 2015) Type 4X were Anti-Aircraft (AAW) frigates (this later evolved into the "Destroyer" Type series). Type 6X were Aircraft-Direction (ADW) frigates. Type 8X were multi-role ships. An Admiralty Fleet Order defined these ships as "destroyers" if they could achieve "fleet speed" or as "sloops" if they could not.

Types 11-30, anti-submarine frigates

Types 31-40, general purpose frigates

Types 41-60, anti-aircraft frigates/destroyers

Types 61-80, aircraft direction frigates

Types 81-99, general purpose frigates/destroyers/sloops